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Polynomials

Class 9th Mathematics RS Aggarwal And V Aggarwal Solution
Exercise 2a
  1. Which of the following expressions are polynomials? (i) x^5 - 2x^3 + x+7 (ii)…
  2. Write the degree of each of the following polynomials: (i) 2x - root 5 (ii)…
  3. Write: (i) Coefficient of x^3 in 2x+x^2 - 5x^3 + x^4 (ii) Coefficient of x root…
  4. Give an example of a binomial of degree 27.
  5. Give an example of a monomial of degree 16.
  6. Give an example of a trinomial of degree 3.
  7. Classify the following as linear, quadratic and cubic polynomials: (i) 2x^2 + 4x…
Exercise 2j
  1. x^3 + 27 Factorize:
  2. 8x^3 + 27y^3 Factorize:
  3. 343 + 125 b^3 Factorize:
  4. 1 + 64x^3 Factorize:
  5. 125a^3 + 1/8 Factorize:
  6. 216x^3 + 1/125 Factorize:
  7. 16x^4 + 54x Factorize:
  8. 7a^3 + 56b^3 Factorize:
  9. x^5 + x^2 Factorize:
  10. a^3 + 0.008 Factorize:
  11. x^6 + y^6 Factorize:
  12. 2a^3 + 16b^3 - 5a - 10b Factorize:
  13. x^3 + 512 Factorize:
  14. 64x^3 - 343 Factorize:
  15. 1 - 27 x^3 Factorize:
  16. x^3 - 125y^3 Factorize:
  17. 8x^3 - 1/27y^3 Factorize:
  18. a^3 - 0.064 Factorize:
  19. (a + b)^3 - 8 Factorize:
  20. x^6 - 729 Factorize:
  21. (a + b)^3 - (a - b)^3 Factorize:
  22. x^6 - 729 Factorize:
  23. 32x^4 - 500x Factorize:
  24. 3a^7 b - 81a^4 b^4 Factorize:
  25. a^3 - 1/a^3 - 2a + 2/a Factorize:
  26. 8a^3 - b^3 - 4ax + 2bx Factorize:
  27. a^3 + 3a^2 b + 3ab^2 + b^3 - 8 Factorize:
Exercise 2k
  1. 125a^3 + b^3 + 64c^3 - 60abc Factorize:
  2. a^3 + 8b^3 + 64c^3 - 24abc Factorize:
  3. 1 + b^3 + 8c^3 - 6bc Factorize:
  4. 216 + 27b^3 + 8c^3 - 108bc Factorize:
  5. 27a^3 - b^3 + 8c^3 + 18abc Factorize:
  6. 8a^3 + 125b^3 - 64c^3 + 120abc Factorize:
  7. 8 - 27b^3 - 343c^3 - 126bc Factorize:
  8. 125 - 8x^3 - 27y^3 - 90xy Factorize:
  9. 2 root 2a^3 + 16 root 2b^3 + c^3 - 12abc Factorize:
  10. x^3 + y^3 - 12xy + 64 Factorize:
  11. (a - b)^3 + (b - c)^3 + (c - a)^3 Factorize:
  12. (3a - 2b)^3 + (2b - 5c)^3 + (5c - 3a)^3 Factorize:
  13. a^3 (b - c)^3 + b^3 (c - a)^3 + c^3 (a - b)^3 Factorize:
  14. (5a - 7b)^3 + (9c - 5a)^3 + (7b - 9c)^3 Factorize:
  15. (x + y - z)(x^2 + y^2 + z^2 - xy + yz + zx) Find the product:
  16. (x -2y - 3)(x^2 + 4y^2 + 2xy - 3x + 6y + 9) Find the product:
  17. (x - 2y - z)(x^2 + 4y^2 + z^2 + 2xy + zx + 2yz) Find the product:…
  18. If x+y+4 = 0 find the value of (x^3 + y^3 - 12xy+64)
  19. If x = 2y+6 find the value of (x^3 - 8y^3 - 36xy-216)
Cce Questions
  1. Which of the following expressions is a polynomial in one variable?A. x + 2/x + 3 B. 3…
  2. Which of the following expressions is a polynomial?A. root x-1 B. x-1/x+1 C. x^2 -…
  3. Which of the following is a polynomial?A. cube root y+4 B. root y-3 C. y D. 1/root y +…
  4. Which of the following is a polynomial?A. x - 1/x + 2 B. 1/x + 5 C. root x+3 D. -4…
  5. Which of the following is a polynomial?A. x^-2 + x^-1 + 3 B. x+x^-1 + 2 C. x^-1 D. 0…
  6. Which of the following is a quadratic polynomial?A. x+4 B. x^3 + x C. x^3 + 2x+6 D. x^2…
  7. Which of the following is a linear polynomial?A. x+x^2 B. x+1 C. 5x^2 - x+3 D. x + 1/x…
  8. Which of the following is a binomial?A. x^2 + x+3 B. x^2 + 4 C. 2x^2 D. x+3 + 1/x…
  9. root 3 is a polynomial of degreeA. 1/2 B. 2 C. 1 D. 0
  10. Degree of the zero polynomial isA. 1 B. 0 C. not defined D. none of these…
  11. Zero of the polynomial p(x) = 2x + 3 isA. 3/2 B. -3/2 C. -2/3 D. 1/2…
  12. Zero of the polynomial p(x) = 2 - 5x isA. 2/5 B. 5/2 C. -2/5 D. -5/2…
  13. Zero of the zero polynomial isA. 0 B. 1 C. every real number D. not defined…
  14. If p(x) = x + 4, then p(x) + (-x) =?A. 0 B. 4 C.2x D. 8
  15. If p (x) = x^2 - 2 root 2x+1 then p (2 root 2) = ? A. 0 B. 1 C. 4 root 2 D. -1…
  16. The zeroes of the polynomial p (x) = x^2 + x - 6 areA. 2, 3 B. -2, 3 C. 2, -3 D. -2,…
  17. The zeroes of the polynomial p (x) = 2x^2 + 5x - 3 areA. 1/2 , 3 B. 1/2 ,-3 C. -1/2 ,…
  18. If (x^2 + kx - 3) = (x - 3) (x + 1) then k =?A. 2 B. -2 C. 3 D. -1…
  19. If (x + 1) is a factor of 2x^2 + kx, then k =?A. -3 B. -2 C. 2 D. 4…
  20. The coefficient of the highest power of x in the polynomial 2x^2 - 4x^4 + 5x^2 - x^5 +…
  21. When (x^31 + 31) is divided by (x + 1), the remainder isA. 0 B. 1 C. 30 D. 31…
  22. When p (x) = x^3 - ax^2 + x is divided by (x - a), the remainder isA. 0 B. a C. 2a D.…
  23. When p (x) = (x^3 + ax^2 + 2x + a) is divided by (x + a), the remainder isA. 0 B. a C.…
  24. When p (x) = x^4 + 2x^3 - 3x^2 + x - 1 is divided by (x - 2), the remainder isA. 0 B.…
  25. When p(x) = x^3 - 3x^2 + 4x + 32 is divided by (x + 2), the remainder isA. 0 B. 32 C.…
  26. When p (x) = 4x^3 - 12x^2 + 11x - 5 is divided by (2x - 1), the remainder isA. 0 B. -5…
  27. (x +1) is a factor of the polynomial:A. x^3 - 2x^2 + x + 2 B. x^3 - 2x^2 + x - 2 C.…
  28. 4x^2 + 4x - 3 = ?A. (2x - 1) (2x - 3) B. (2x + 1) (2x - 3) C. (2x - 1) (2x + 3) D.…
  29. 6x^2 + 17x + 5A. (2x - 1) (3x + 5) B. (2x + 5) (3x - 1) C. (6x + 5) (x + 1) D. none of…
  30. x^2 - 4x - 21 = ?A. (x - 3) (x - 7) B. (x - 3) (x + 7) C. (x + 3) (x - 7) D. none of…
  31. If (x + 5) is a factor of p (x) = x^3 - 20x + 5k, then k =?A. -5 B. 5 C. 3 D. -3…
  32. 3x^3 + 2x^2 + 3x + 2 = ?A. (3x - 2) (x^2 - 1) B. (3x -2)(x^2 + 1) C. (3x +2) (x^2 - 1)…
  33. If x/y + y/x = - 1 where x not equal 0 and y not equal 0 then the value of (x^3 - y^3)…
  34. If a + b + c = 0, then a^3 + b^3 + c^3 = ?A. 0 B. abc C. 2abc D. 3abc…
  35. (x + 2) and (x - 1) are factors of (x^3 + 10x^2 + mx + n) thenA. m = 5, n = -3 B. m =…
  36. The value of (369)^2 - (368)^2 = ?A. 1^2 B. 81 C. 37 D. 737
  37. 104 x 96 =?A. 9894 B. 9984 C. 9684 D. 9884
  38. 4a^2 + b^2 + 4ab + 8a + 4b + 4 = ?A. (2a + b + 2)^2 B. (2a - b + 2)^2 C. (a + 2b +…
  39. The coefficient of x in the expansion of (x + 3)^3 isA. 1 B. 9 C. 18 D. 27…
  40. If a + b + c = 0, then (a^3/bc + b^2/ca + c^3/ab) = ? A. 1 B. 0 C. -1 D. 3…
  41. If x + y + z = 9 and xy + yz + zx = 23, then the value of (x^3 + y^3 + z^3 - 3xyz) =…
  42. If (x^100 + 2x^99 + k) is divisible by (x + 1), then the value of k isA. 1 B. 2 C. -2…
  43. In a polynomial in x, the indices of x must beA. Integers B. Positive integers C.…
  44. For what value of k is the polynomial p (x) = 2x^3 - kx^2 + 3x + 10 exactly divisible…
  45. 207 x 193 =?A. 39851 B. 39951 C. 39961 D. 38951
  46. 305 x 308 =?A. 94940 B. 93840 C. 93940 D. 94840
  47. The zeroes of the polynomial p (x) = x^2 - 3x areA. 0, 0 B. 0, 3 C. 0, -3 D. 3, -3…
  48. The zeroes of the polynomial p (x) = 3x^2 - 1 areA. 1/3 B. 1/root 3 C. -1/root 3 D.…
  49. Assertion (A) Reason (R) If (x - 1) is a factor of p (x) = x^2 + kx+1 then k = - 2 If…
  50. Assertion (A) Reason (R) If p (x) = x^3 - ax^2 + 6x-a is divided by (x - a), then the…
  51. Assertion (A) Reason (R) If (x - 2) is a factor of p (x) = x^3 - 2x+3k then -4/3 If…
  52. Assertion (A) Reason (R) The value of (25)^3 + (-16)^3 + (-9)^3 is 10800. If a + b + c…
  53. Column I Column II (a) If p (x) = x^3 - 2x^2 + 3x + 1 is divided by (x + 1), then…
  54. Column I Column II (a) If p (x) = 81x^4 + 54x^3 - 9x^2 - 3x + 2 is divided by (3x +…
Formative Assessment (unit Test)
  1. Let p (x) = 3x^3 + 4x^2 - 3x+8 Find p(-2).
  2. Find the remainder when p (x) = 4x^3 + 8x^2 - 17x + 10 is divided by (2x - 1).…
  3. If (x - 2) is a factor of 2x^3 - 7x^2 + 11x + 5a, find the value of a.…
  4. For what value of m, p(x) = (x^3 - 2mx^2 + 16) is divisible by (x + 2)?…
  5. If (a + b + c) = 8 and (ab + bc + ca) = 19, find (a^2 + b^2 + c^2)…
  6. Expand: (3a + 4b + 5c)^2 .
  7. Expand: (3x + 2)^2 .
  8. Evaluate: {(28)^3 + (-15)^3 + (-13)^3 }.
  9. If (x^60 + 60) is divided by (x + 1), the remainder isA. 0 B. 59 C. 61 D. 2…
  10. One of the factors of (36x^2 - 1) + (1 + 6x)^2 isA. (6x - 1) B. (6x + 1) C. 6x D. 6-x…
  11. If then (a^3 - b^3) = ?A. -1 B. -3 C. -2 D. 0
  12. The coefficient of x in the expansion of (x + 5)^3 isA. 1 B. 15 C. 45 D. 75…
  13. root 3 is a polynomial of degreeA. 1/2 B. 2 C. 0 D. 1
  14. One of the zeroes of the polynomial 2x^2 + 7x - 4 isA. 2 B. 1/2 C. -2 D. -1/2…
  15. Zero of the zero polynomial isA. 0 B. 1 C. every real number D. not defined…
  16. If (x + 1) and (x - 1) are factors of p (x) = ax^3 + x^2 - 2x + b, find the values of…
  17. If (x + 2) is a factor of p (x) = ax^3 + bx^2 + x - 6 and p(x) when divided by (x - 2)…
  18. The expanded form of (3x - 5)^3 isA. 27x^3 + 133x^2 + 222x-12x B. 27x^3 + 133x^2 -…
  19. If a + b + c = 5 and ab + bc + ca = 10, prove that a^3 + b^3 + c^3 - 3abc = - 25.…
  20. If p (x) = 2x^3 + ax^2 + 3x - 5 and q (x) = x^3 + x^2 - 4x + a leave the same…
Exercise 2b
  1. If p (x) = 5-4x+2x^2 find (i) p (0) (ii)p(3) (iii) p(-2)
  2. If p (y) = 4+3y-y^2 + 5y^3 find (i) P(0) (ii) p(2) (iii) p(-1)
  3. If f (t) = 4t^2 - 3t+6 find (i) f (0) (ii) f (4) (iii) f (-5)
  4. Find the zero of the polynomial: (i) P(x)=x-5 (ii) q(x)=x+4 (iii) p(t)=2t-3 (iv)…
  5. Verify that: (i) 4 is a zero of the polynomial p(x)=x-4. (ii) -3 is a zero of…
Exercise 2c
  1. (x^3 - 6x^2 + 9x+3) is divided by (x-1)
  2. (2x^35x^2 + 9x-8) is divided by (x-3)
  3. (3x^4 - 6x^2 - 8x+2) is divided by (x-2)
  4. (x^3 - 7x^2 + 6x+4) is divided by (x-6)
  5. (x^3 - 6x^2 + 13x+60) is divided by (x+2)
  6. (2x^4 + 6x^3 + 2x^2 + x-8) is divided by (x+3)
  7. (4x^3 - 12x^2 + 11x-5) is divided by (2x-1)
  8. (81x^4 + 54x^3 - 9x^2 - 3x+2) is divided by (3x+2)
  9. x^3 - ax^2 + 2x-a is divided by (x-a)
  10. The polynomials (ax^3 + 3x^2 - 3) and (2x^3 - 5x+a) when divided by (x-4) leave…
  11. The Polynomial f(x) = x^4 -2x3+3x2-ax + bwhen divided by (x-1) and (x+1) leaves…
Exercise 2d
  1. (x-2) is a factor of (x^3 - 8)
  2. (x-3) is a factor of (2x^3 + 7x^2 - 24x-45)
  3. (x-1) is a factor of (2x^4 + 9x^3 + 6x^2 - 11x-6)
  4. (x+2) is a factor of (x^4 - x^2 - 12)
  5. (x+5) is a factor of (2x^3 + 9x^2 - 11x-30)
  6. (2x-3) is a factor of (2x^4 + x^3 - 8x^2 - x+6)
  7. (x - root 2) is a factor of (7x^2 - 4 root 2x-6)
  8. (x + root 2) is a factor of (2 root 2x^2 + 5x + root 2)
  9. Find the value of k for which (x-1) is a factor of (2x^3 + 9x^2 + x+k)…
  10. Find the value of a for which (x-4) is a factor of (2x^3 - 3x^2 - 18x+a)…
  11. Find the value of a for which the polynomial (x^4 - x^3 - 11x^2 - x+a) is…
  12. For what value of a is the polynomial (2x^3 + ax^2 + 11x+a+3) exactly divisible…
  13. Find the values of a and b so that the polynomial (x^3 - 10x^2 + ax+b) is…
  14. Find the values of a and b so that the polynomial (x^4 + ax^3 - 7x^2 - 8x+b) is…
  15. Without actual division, show that (x^3 - 3x^2 - 13x+15) is exactly divisible…
  16. If (x^3 + ax^2bx+6) has (x-2) as a factor and leaves a remainder 3 when divided…
Exercise 2e
  1. 9x^2 + 12xy Factorize:
  2. 18x^2 y - 24 xyz Factorize:
  3. 27a^3 b^3 - 45a^4 b^2 Factorize:
  4. 2a(x + y) -3b(x + y) Factorize:
  5. 2x(p^2 + q^2) +4y (p^2 + q^2) Factorize:
  6. x(a - 5) + y (5 - a) Factorize:
  7. 4(a + b) - 6 (a + b)^2 Factorize:
  8. 8(3a - 2b)^2 - 10 (3a - 2b) Factorize:
  9. x(x + y)^3 - 3x^2 y (x + y) Factorize:
  10. x^3 + 2x^2 + 5x + 10 Factorize:
  11. x^2 + xy - 2xz - 2yz Factorize:
  12. a^3 b - a^2 b + 5ab - 5b Factorize:
  13. 8 - 4a - 2a^3 + a^4 Factorize:
  14. x^3 - 2x^2 y + 3xy^2 - 6y^3 Factorize:
  15. px - 5q + pq - 5x Factorize:
  16. x^2 + y - xy - x Factorize:
  17. (3a - 1)^2 - 6a + 2 Factorize:
  18. (2x - 3)^2 - 8x + 12 Factorize:
  19. a^2 + a - 3a^2 - 3 Factorize:
  20. 3ax - 6ay - 8by + 4bx Factorize:
  21. abx^2 + a^2 x + b^2 x + ab Factorize:
  22. x^3 - x^2 + ax + x - a - 1 Factorize:
  23. 2x + 4y - 8xy - 1 Factorize:
  24. ab(x^2 + y^2) - xy(a^2 + b^2) Factorize:
  25. a^2 + ab(b + 1) + b^3 Factorize:
  26. a^3 + ab(1 - 2a) - 2b^2 Factorize:
  27. 2a^2 + bc - 2ab - ac Factorize:
  28. (ax + by)^2 + (bx - ay)^2 Factorize:
  29. a(a + b - c) - bc Factorize:
  30. a(a - 2b - c) + 2bc Factorize:
  31. a^2 x^2 + (ax^2 + 1)x + a Factorize:
  32. ab(x^2 + 1) + x(a^2 + b^2) Factorize:
  33. x^2 - (a + b)x + ab Factorize:
  34. x^2 + 1/x^2 - 2-3x + 3/x Factorize:
Exercise 2f
  1. 25x^2 - 64y^2 Factorize:
  2. 100 - 9x^2 Factorize:
  3. 5x^2 - 7y^2 Factorize:
  4. (3x + 5y)^2 - 4z^2 Factorize:
  5. 150 - 6x^2 Factorize:
  6. 20x^2 - 45 Factorize:
  7. 3x^3 - 48 Factorize:
  8. 2 - 50x^2 Factorize:
  9. 27a^2 - 48b^2 Factorize:
  10. x - 64x^3 Factorize:
  11. 8ab^2 - 18a^3 Factorize:
  12. 3a^3 b - 243ab^3 Factorize:
  13. (a + b)^3 - a - b Factorize:
  14. 108a^2 -3(b - c)^2 Factorize:
  15. x^3 - 5x^2 - x + 5 Factorize:
  16. a^2 + 2ab + b^2 - 9c^2 Factorize:
  17. 9 - a^2 + 2ab - b^2 Factorize:
  18. a^2 - b^2 -4ac + 4c^2 Factorize:
  19. 9a^2 + 3a - 8b - 64b^4 Factorize:
  20. x^2 - y^2 + 6y - 9 Factorize:
  21. 4x^2 - 9y^2 - 2x - 3y Factorize:
  22. x^4 - 1 Factorize:
  23. a - b - a^2 + b^2 Factorize:
  24. x^4 - 625 Factorize:
Exercise 2g
  1. x^2 + 11x + 30 Factorize:
  2. x^2 + 18x + 32 Factorize:
  3. x^2 + 7x - 18 Factorize:
  4. x^2 + 5x - 6 Factorize:
  5. y^2 - 4y + 3 Factorize:
  6. x^2 - 21x + 108 Factorize:
  7. x^2 - 11x - 80 Factorize:
  8. x^2 - x - 156 Factorize:
  9. z^2 - 32z - 105 Factorize:
  10. 40 + 3x - x^2 Factorize:
  11. 6x - x - x^2 Factorize:
  12. 7x^2 + 49x + 84 Factorize:
  13. m^2 + 17mn - 84 Factorize:
  14. 5x^2 + 16x + 3 Factorize:
  15. 6x^2 + 17x + 12 Factorize:
  16. 9x^2 + 18x + 8 Factorize:
  17. 14x^2 + 9x + 1 Factorize:
  18. 2x^2 + 3x - 90 Factorize:
  19. 2x^2 + 11x - 21 Factorize:
  20. 3x^2 - 14x + 8 Factorize:
  21. 18x^2 + 3x - 10 Factorize:
  22. 15x^2 + 2x - 8 Factorize:
  23. 6x^2 + 11x - 10 Factorize:
  24. 30x^2 + 7x - 15 Factorize:
  25. 24x^2 - 41x + 12 Factorize:
  26. 2x^2 - 7x - 15 Factorize:
  27. 6x^2 - 5x - 21 Factorize:
  28. 10x^2 - 9x - 7 Factorize:
  29. 5x^2 - 16x - 21 Factorize:
  30. 2x^2 - x - 21 Factorize:
  31. 15x^2 - x - 28 Factorize:
  32. 8a^2 - 27ab + 9b^2 Factorize:
  33. 5x^2 + 33xy - 14y^2 Factorize:
  34. 3x^3 - x^2 - 10x Factorize:
  35. 1/3 x^2 - 2x-9 Factorize:
  36. x^2 - 2x + 7/16 Factorize:
  37. root 2x^2 + 3x + root 2 Factorize:
  38. root 5x^2 + 2x-3 root 5 Factorize:
  39. 2x^2 + 3 root 3x+3 Factorize:
  40. 2 root 3x^2 + x-5 root 3 Factorize:
  41. 5 root 5x^2 + 20x+3 root 5 Factorize:
  42. 7 root 2x^2 - 10x-4 root 2 Factorize:
  43. 6 root 3x^2 - 47x+5 root 3 Factorize:
  44. 7x^2 + 2 root 14x+2 Factorize:
  45. 2(x + y)^2 -9(x + y) - 5 Factorize:
  46. 9(2a - b)^2 - 4(2a - b) - 13 Factorize:
  47. 7(x - 2y)^2 - 25(x - 2y) + 12 Factorize:
  48. 4x^4 + 7x^2 - 2 Factorize:
Exercise 2h
  1. Expand: (i) (a + 2b + 5c)^2 (ii) (2a - b + c)^2 (iii) (a - 2b - 3c)^2…
  2. Expand (i) (2a - 5b - 7c)^2 (ii) (-3a + 4b - 5c)^2 (iii) (1/2 a - 1/4 b+2)^2…
  3. 4x^2 + 9y^2 + 16z^2 + 12xy - 24yz - 16xz Factorize:
  4. 9x^2 + 16y^2 + 4z^2 -24xy + 16yz - 12xz Factorize:
  5. 25x^2 + 4y^2 + 9z^2 - 20xy - 12yz + 30xz Factorize:
  6. Evaluate: (i) (99)^2 (ii) (998)^2
Exercise 2i
  1. (i) (3x + 2)^2 (ii) (3a - 2b)^2 (iii) (2/3 x+1)^3 Expand:
  2. (i) (2x - 2/x)^3 (ii) (3a + 1/4b)^3 (iii) (4/5 x-2)^3 Expand:
  3. Evaluate: (i) (95)^3 (ii) (999)^3

Exercise 2a
Question 1.

Which of the following expressions are polynomials?

(i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

(viii)

(ix)

(x) 1

(xi)

(xii)

In case of a polynomial, write its degree.


Answer:

(i)


Yes,


The given expression is a polynomial


This is because all the variables have integer exponents that are positive.


Since, the highest power of the variable is 5.


Hence, the degree of the polynomial is 5.


(ii)


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 3


Hence, the degree of the polynomial is 3


(iii)


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 2


Hence, the degree of the polynomial is 2


(iv)


No,


The given expression is not a polynomial


Since, the term has a fractional exponent.


(v)


No,


The given expression is not a polynomial


Since, the term has a negative exponent.


(vi)


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 108


Hence, the degree of the polynomial is 108


(vii)


No,


The given expression is not a polynomial


Since, the term has a fractional exponent.


(viii)


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 2


Hence, the degree of the polynomial is 2


(ix)


No,


The given expression is not a polynomial


Since, the term has a negative exponent.


(x) 1


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 0


Hence, the degree of the polynomial is 0


(xi)


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 0


Hence, the degree of the polynomial is 0


(xii)


Yes,


The given expression is a polynomial


This is because all of the variables have integer exponents that are positive.


Since, the highest power of the variable is 2


Hence, the degree of the polynomial is 2



Question 2.

Write the degree of each of the following polynomials:

(i)

(ii)

(iii) 9

(iv)

(v)

(vi)


Answer:

(i)


Since,


In the given polynomial, the highest power of the variable is 1


Hence,


The degree of the polynomial is 1


(ii)


Since,


In the given polynomial, the highest power of the variable is 3


Hence,


The degree of the polynomial is 3


(iii) 9


Since,


In the given polynomial, the highest power of the variable is 0


Hence,


The degree of the polynomial is 0


(iv)


Since,


In the given polynomial, the highest power of the variable is 7


Hence,


The degree of the polynomial is 7


(v)


Since,


In the given polynomial, the highest power of the variable is 10


Hence,


The degree of the polynomial is 10


(vi)


Since,


In the given polynomial, the highest power of the variable is 2


Hence,


The degree of the polynomial is 2



Question 3.

Write:

(i) Coefficient of in

(ii) Coefficient of

(iii) Coefficient of in

(iv) Coefficient of in


Answer:

(i)


Hence,


The Coefficient of in the given polynomial is -5


(ii)


Hence,


The Coefficient of x in the given polynomial is -22


(iii)


Hence,


The Coefficient of in the given polynomial is


(iv) 3x – 5


Since,


There isn’t any variable with exponent as 2


Hence,


The Coefficient of in the given polynomial, is 0



Question 4.

Give an example of a binomial of degree 27.


Answer:

An example of a binomial of degree 27 is a two-term polynomial with highest degree 27.


Hence,


The suitable example for the question can be y27 – 29.



Question 5.

Give an example of a monomial of degree 16.


Answer:

An example of a monomial of degree 16 is a single term polynomial with highest degree 16.


Hence,


The suitable example for the question can be y16



Question 6.

Give an example of a trinomial of degree 3.


Answer:

An example of a trinomial of degree is a three-term polynomial with highest degree 3.


Hence,


The suitable example for the question can be y3 –y2 + 29



Question 7.

Classify the following as linear, quadratic and cubic polynomials:

(i)

(ii)

(iii)

(iv) -7+z

(v) (vi)


Answer:

(i)


Since,


The degree of the given polynomial is 2


Hence,


The polynomial is a quadratic polynomial.


(ii)


Since,


The degree of the given polynomial is 3


Hence,


The polynomial is a cubic polynomial.


(iii)


Since,


The degree of the given polynomial is 2


Hence,


The polynomial is a quadratic polynomial.


(iv) -7+z


Since,


The degree of the given polynomial is 1


Hence,


The polynomial is a linear polynomial.


(v)


Since,


The degree of the given polynomial is 1


Hence,


The polynomial is a linear polynomial.


(vi)


Since,


The degree of the given polynomial is 3


Hence,


The polynomial is a cubic polynomial.




Exercise 2j
Question 1.

Factorize:

x3 + 27


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= x3 + 33


= (x + 3) (x2 – 3x + 9)



Question 2.

Factorize:

8x3 + 27y3


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (2x)3 + (3y)3


= (2x + 3y) [(2x)2 – (2x) (3y) + (3y)2]


= (2x + 3y) (4x2 – 6xy + 9y2)



Question 3.

Factorize:

343 + 125 b3


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (7)3 + (5b)3


= (7 + 5b) [(7)2 – (7) (5b) + (5b)2]


= (7 + 5b) (49 – 35b + 25b2)



Question 4.

Factorize:

1 + 64x3


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (1)3 + (4x)3


= (1 + 4x) [(1)2 – 1 (4x) + (4x)2]


= (1 + 4x) (1 – 4x + 16x2)



Question 5.

Factorize:



Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (5a)3 + ()3


= (5a + ) [ (5a)2 – 5a × + ()2]


= (5a + ) (25a2 - + )



Question 6.

Factorize:



Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (6x)3 + ()3


= (6x + ) [(6x)2 – 6x × + ()2]


= (6x + ) (36x2 - + )



Question 7.

Factorize:

16x4 + 54x


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= 2x (8x3 + 27)


= 2x [(2x)3 + (3)3]


= 2x (2x + 3) [(2x)2 – 2x(3) + 32]


= 2x (2x + 3) (4x2 – 6x + 9)



Question 8.

Factorize:

7a3 + 56b3


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= 7 (a3 + 8b3)


= 7 (a + 2b) (a2 – a × 2b + (2b)2]


= 7 (a + 2b) (a2 – 2ab + 4b2)



Question 9.

Factorize:

x5 + x2


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= x2 (x3 + 1)


= x2 (x + 1) [(x2) – x (1) + (1)2]


= x2 (x + 1) (x2 – x + 1)



Question 10.

Factorize:

a3 + 0.008


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (a)3 + (0.2)3


= (a + 0.2) [(a)2 – a (0.2) + (0.2)2]


= (a + 0.2) (a2 – 0.2a + 0.04)



Question 11.

Factorize:

x6 + y6


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (x2)3 + (y2)3


= (x2 + y2) [(x2)2 – x2(y2) + (y2)2]


= (x2 + y2) (x4 – x2y2 + y4)



Question 12.

Factorize:

2a3 + 16b3 – 5a – 10b


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= 2 (a3 + 8b3) – 5 (a + 2b)


= 2 [(a)3 + (2b)3] – 5 (a + 2b)


= 2 (a + 2b) [(a)2 – a (2b) + (2b)2] – 5 (a + 2b)


= (a + 2b) [2 (a2 – 2ab + 4b2) – 5]



Question 13.

Factorize:

x3 + 512


Answer:

We know that,


a3 + b3 = (a + b) (a2 – a × b + b2)


Using this formula, we get


= (x)3 – (8)3


= (x - 8) [(x)2 + x (8) + (8)2]


= (x – 8) (x2 + 8x + 64)



Question 14.

Factorize:

64x3 – 343


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= (4x)3 – (7)3


= (4x - 7) [(4x)2 + 4x (7) + (7)2)


= (4x – 7) (16x2 + 28x + 49)



Question 15.

Factorize:

1 – 27 x3


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= (1)3 – (3x)3


= (1 – 3x) [(1)2 + 1 (3x) + (3x)2)


= (1 – 3x) (1 + 3x + 9x2)



Question 16.

Factorize:

x3 – 125y3


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= (x)3 – (5y)3


= (x – 5y) [(x)2 + x (5y) + (5y)2


= (x – 5y) (x2 + 5xy + 25y2)



Question 17.

Factorize:



Answer:

We know that,


a3 - b3 = (a - b) (a2+ a × b + b2)


Using this formula, we get


= (2x)3 – ()3


= (2x - ) [(2x)2 + 2x × + ()2]


=



Question 18.

Factorize:

a3 – 0.064


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= (a)3 – (0.4)3


= (a – 0.4) [(a)2 + a (0.4) + (0.4)2]


= (a – 0.4) (a2 + 0.4a + 0.16)



Question 19.

Factorize:

(a + b)3 – 8


Answer:

(a + b)3 – (2)3


We know that,


a3 - b3 = (a - b) (a2+ a × b + b2)


Using this formula, we get


= (a + b – 2) [(a + b)2 + (a + b) 2 + (2)2]


= (a + b – 2) [a2 + b2 + 2ab + 2 (a + b) + 4]



Question 20.

Factorize:

x6 – 729


Answer:

We know that,


a3 - b3 = (a - b) (a2+ a × b + b2)


Using this formula, we get


= (x2)3 – (9)3


= (x2 – 9) [(x2)2 + x29 + (9)2]


= (x2 – 9) (x4 + 9x2 + 81)


= (x + 3) (x – 3) [(x2 + 9)2 – (3x)2]


= (x + 3) (x – 3) (x2 + 3x + 9) (x2 – 3x + 9)



Question 21.

Factorize:

(a + b)3 – (a – b)3


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= [a + b – (a – b)] [(a + b)2 + (a + b) (a – b) + (a – b)2]


= (a + b – a + b) [a2 + b2 + 2ab + a2 – b2 + a2 + b2 – 2ab]


= 2b (3a2 + b2)



Question 22.

Factorize:

x6 – 729


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= x (1 – 8y3)


= x [(1)3 – (2y)3]


= x (1 – 2y) [(1)2 + 1 (2y) + (2y)2]


= x (1 – 2y) (1 + 2y + 4y2)



Question 23.

Factorize:

32x4 – 500x


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= 4x (8x3 – 125)


= 4x [(2x)3 – (5)3]


= 4x [(2x – 5) [(2x)2 + 2x (5) + (5)2]


= 4x (2x – 5) (4x2 + 10x + 25)



Question 24.

Factorize:

3a7b – 81a4b4


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= 3a4b (a3 – 27b3)


= 3a4b [(a)3– (3b)3]


= 3a4b (a – 3b) [(a)2 + a (3b) + (3b)2]


= 3a4b (a – 3b) (a2 + 3ab + 9b2)



Question 25.

Factorize:



Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= a3 - 1/a3 – 2 (a – 1/a)


= (a – 1/a) (a2 + a × 1/a + 1/a2) – 2 (a – 1/a)


= (a – 1/a) (a2 + 1 + 1/a2 – 2)


=



Question 26.

Factorize:

8a3 – b3 – 4ax + 2bx


Answer:

We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= 8a3 – b3 – 2x (2a – b)


= (2a)3 – (b)3 – 2x (2a – b)


= (2a – b) [(2a)2 + 2a (b) + (b)2] – 2x (2a – b)


= (2a – b) (4a2 + 2ab + b2) – 2x (2a – b)


= (2a – b) (4a2 + 2ab + b2 – 2x)



Question 27.

Factorize:

a3 + 3a2b + 3ab2 + b3 – 8


Answer:

We know that,


(a + b)3 = a3 + b3 + 3ab (a + b)


Using this formula, we get


= (a + b)3 – 8


= (a + b)3 – (2)3


We know that,


a3 - b3 = (a - b) (a2 + a × b + b2)


Using this formula, we get


= (a + b – 2) [(a+ b)2 + 2 (a + b) + 4)]




Exercise 2k
Question 1.

Factorize:

125a3 + b3 + 64c3 – 60abc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (5a)3 + (b)3 + (4c)3 – 3 (5a) (b) (4c)


= (5a + b + 4c) [(5a)2 + b2 + (4c)2 – (5a) (b) – (b) (4c) – (5a) (4c)]


= (5a + b + 4c) (25a2 + b2 + 16c2 – 5ab – 4bc – 20ac)



Question 2.

Factorize:

a3 + 8b3 + 64c3 – 24abc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (a)3 + (2b)3 + (4c)3 – 3 (a) (2b) (4c)


= (a + 2b + 4c) (a2 + 4b2 + 16c2 – 2ab – 8bc – 4ac)



Question 3.

Factorize:

1 + b3 + 8c3 – 6bc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (1)3 + (b)3 + (2c)3 – 3 (1) (b) (2c)


= (1 + b + 2c) [(1)2 + (b)2 + (4c)2 – (1) (b) – (2b) (c) – (2c) (1)]


= (1 + b + 2c) (1 + b2 + 4c2 – b – 2bc – 2c)



Question 4.

Factorize:

216 + 27b3 + 8c3 – 108bc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (6)3 + (3b)3 + (2c)3 – 3 (6) (3b) (2c)


= (6 + 3b + 2c) [(6)2 + (3b)2 + (2c)2 – (6) (3b) – (3b) (2c) – (2c) (6)]


= (6 + 3b + 2c) (36 + 9b2 + 4c2 – 18ab – 6bc – 12ac)



Question 5.

Factorize:

27a3 – b3 + 8c3 + 18abc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (3a)3 + (-b)3 + (2c)3 – 3 (3a) (-b) (2c)


= [3a + (-b) + 2c] [(3a)2 + (-b)2 + (2c)2 – (3a) (-b) – (-b) (2c) – (2c) (3a)]


= (3a - b + 2c) (9a2 + b2 + 4c2+ 3ab + 2bc – 6ca)



Question 6.

Factorize:

8a3 + 125b3 – 64c3 + 120abc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (2a)3 + (5b)3 + (-4c)3 – 3 (2a) (5b) (-4c)


= (2a + 5b - 4c) [(2a)2 + (5b)2 + (-4c)2 – (2a) (5b) – (5b) (-4c) – (-4c) (2a)]


= (2a + 5b - 4c) (4a2 + 25b2 + 16c2 – 10ab + 20bc + 8ca)



Question 7.

Factorize:

8 – 27b3 – 343c3 – 126bc


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (2)3 + (-3b)3 + (-7c)3 – 3 (2) (-3b) (-7c)


= (2 - 3b - 7c) [(2)2 + (-3b)2 + (-7c)2 – (2) (-3b) – (-3b) (-7c) – (-7c) (2)]


= (2 - 3b - 7c) (4 + 9b2 + 49c2 + 6b – 21bc + 14c)



Question 8.

Factorize:

125 – 8x3 – 27y3 – 90xy


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (5)3 + (-2x)3 + (-3y)3 – 3 (5) (-2x) (-3y)


= (5 – 2x – 3y) [(5)2 + (-2x)2 + (-3y)2 – (5) (-2x) – (-2x) (-3y) – (-3y) (5)]


= (5 – 2x – 3y) (25 + 4x2 + 9y2 + 10x – 6xy + 15y)



Question 9.

Factorize:



Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (a)3 + (2b)3 + (c)3 – 3 (a) (2b) (c)


= ( + 2b + c) [()2 + (2b)2 + (c)2 – () (2b) – (2b) (c) – (c) (a)]


= ( + 2b + c) (2a2 + 8b2 + c2 – 4ab – 2bc – ac)



Question 10.

Factorize:

x3 + y3 – 12xy + 64


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


= (x)3 + (y)3 + (4)3 – 3 (x) (y) (4)


= (x + y + 4) [(x)2 + (y)2 + (4)2 – (x) (y) – (y) (4) – (4) (x)]


= (x + y + 4) (x2 + y2 + 16 –xy – 4y – 4x)



Question 11.

Factorize:

(a – b)3 + (b – c)3 + (c – a)3


Answer:

We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Using this formula, we get


Putting (a – b) = x, (b – c) = y and (c – a) = z, we get


(a - b)3 + (b - c)3 + (c - a)3= x3 + y3 + z3


Where (x + y + z) = (a – b) + (b – c) + (c – a) = 0


= 3xyz [Since, (x + y + z) = 0 so (x3 + y3 + z3) = 3xyz]


= 3 (a – b) (b – c) (c – a)



Question 12.

Factorize:

(3a – 2b)3 + (2b – 5c)3 + (5c – 3a)3


Answer:

We know that,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


We have,


(3a – 2b) (2b – 5c) + (5c – 3a) = 0


So,


(3a – 2b)3 + (2b – 5c)3 + (5c – 3a)3 = 3 (3a – 2b) (2b – 5c) (5c – 3a)



Question 13.

Factorize:

a3(b – c)3 + b3(c – a)3 + c3(a – b)3


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


= [a (b – c)]3 + [b (c – a)]3 + [c (a – b)]3


Since,


a (b – c) + b (c – a) + c (a – b) = ab – ac + bc – ba + ca – bc = 0


So,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


= 3a (b – c) b (c – a) c (a – b)


= 3abc (a – b) (b – c) (c – a)



Question 14.

Factorize:

(5a – 7b)3 + (9c – 5a)3 + (7b – 9c)3


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


Since,


(5a – 7b) + (9c – 5a) + (7b – 9c) = 5a – 7b + 9c – 5a + 7b – 9c = 0


Therefore,


(5a – 7b)3 + (9c – 5a)3 + (7b – 9c)3 = 3 (5a – 7b) (9c – 5a) (7b – 9c)



Question 15.

Find the product:

(x + y – z)(x2 + y2 + z2 – xy + yz + zx)


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


Using this, we get


= [x + y + (-z)] [(x)2 + (y)2 + (-z)2 – (x) (y) – (y) (-z) – (-z) (x)]


= x3 + y3 – z3 + 3xyz



Question 16.

Find the product:

(x –2y – 3)(x2 + 4y2 + 2xy – 3x + 6y + 9)


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


Using this, we get


= [x + (-2y) + 3] [(x)2 + (-2y)2 + (3) – (x) (-2y) – (-2y) (3) – (3) (x)]


= (a + b + c) (a2 + b2 + c2 – ab – bc – ca)


= a# + b3 + c3 – 3abc


Where,


x = a, b = -2y and c = 3


(x – 2y + 3) (x2 + 4y2 + 2xy – 3x + 6y + 9)


= (x)3 + (-2y)3 + (3)3 – 3 (x) (-2y) (3)


= x3 – 8y3 + 27 + 18xy



Question 17.

Find the product:

(x – 2y – z)(x2 + 4y2 + z2 + 2xy + zx + 2yz)


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


Using this, we get


= [x + (-2y) + (-z)] [(x)2 + (-2y)2 + (-z)2 – (x) (-2y) – (-2y) (-z) – (-z) (x)


= (a + b + c) (a2 + b2 + c2 – ab – bc – ca)


= a3 + b3 + c3 – 3abc


Where,


x = a, b = -2y and c = -z


(x – 2y – z) (x2 + 4y2 + z2 + 2xy + zx – 2yz)


= (x)3 + (-2y)3 + (-z)3 – 3 (x) (-2y) (-z)


= x3 – 8y3 – z3 – 6xyz



Question 18.

If find the value of


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


Given,


x + y + 4 = 0


We have,


(x3 + y3 – 12xy + 64)


= (x)3 + (y)3 + (4)3 – 3 (x) (y) (4) = 0



Question 19.

If find the value of


Answer:

We have,


a3 (b – c)3 + b3 (c – a)3 + c3 (a – b)3


We know that,


a3 + b3 + c3 – 3abc = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)]


Also,


If, (x + y + z) = 0


Then (x3 + y3 + z3) = 3xyz


Given, x = 2y + 6


Or, x – 2y – 6 = 0


We have,


(x3 – 8y3 – 36xy – 216)


= (x3 – 8y3 – 216 – 36xy)


= (x)3 + (-2y)3 + (-6)3 – 3 (x) (-2y) (-6)


= (x – 2y – 6) [(x)2 + (-2y)2 + (-6)2 – (x) (-2y) – (-2y) (-6) – (-6) (x)]


= (x – 2y – 6) (x2 + 4y2 + 36 + 2xy – 12y + 8x)


= 0 (x2 + 4y2 + 36 + 2xy – 12y + 6x)


= 0




Cce Questions
Question 1.

Which of the following expressions is a polynomial in one variable?
A.

B.

C.

D.


Answer:

Polynomials in one variable are algebraic expressions that consist of terms having same variable all through


∴ since in the expression the only polynomial used is x.


Hence, option C is correct


Question 2.

Which of the following expressions is a polynomial?
A.

B.

C.

D.


Answer:

*Note: A polynomial is an expression having variables and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.


Now, and is not a polynomial because it does not contain integer power of the variable “x”.


And, is not a polynomial because it contains a negative power of the variable, which is not the criteria for a polynomial.


is a polynomial it contains only integral powers of the variable (x) i.e. x2


Hence, option D is correct


Question 3.

Which of the following is a polynomial?
A.
B.

C.

D.


Answer:

*Note: A polynomial is an expression having variables and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables


and is not a polynomial because it does not contain integer power of the variable “y”


And, is not a polynomial because it contains a negative power of the variable, which is not the criteria for a polynomial.


∴ y is a polynomial as it follows the criteria of polynomial and all the other do not follow these criteria.


Hence, option C is correct


Question 4.

Which of the following is a polynomial?
A.

B.

C.

D.


Answer:

As we know that,

A polynomial is an expression having variables and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables


Out of the 4 given options, we have:


and are not polynomials as they have negative exponent.


is not a polynomial as it has non integral exponent.


And -4 can be written as -4x0, thus it is a polynomial with integer power.


Thus, -4 is the correct option.


Question 5.

Which of the following is a polynomial?
A.

B.

C.

D.


Answer:

Out of the 4 given options, D is the correct option because all the other has negative exponential​ value which shows that they aren't a polynomial


Question 6.

Which of the following is a quadratic polynomial?
A.

B.

C.

D.


Answer:

A quadratic polynomial is a polynomial of degree 2 which means that it must have a variable with degree 2.

∴ x2 + 5x + 4 is a quadratic polynomial


Hence, option D is correct


Question 7.

Which of the following is a linear polynomial?
A.

B.

C.

D.


Answer:

x + 1 is a linear polynomial because it has degree one which means that highest power of the variable must be 1

Hence, option B is correct


Question 8.

Which of the following is a binomial?
A.

B.

C.

D.


Answer:

In algebra, a binomial is a polynomial which is the sum of two terms, each of which is a monomial. It is the simplest kind of polynomial after the monomials

∴ x2 + 4 is a binomial


Hence, option B is correct


Question 9.

is a polynomial of degree
A.

B.

C.

D.


Answer:

is a polynomial of degree 0 this is because it do not have any variable

Hence, option D is correct


Question 10.

Degree of the zero polynomial is
A. 1

B. 0

C. not defined

D. none of these


Answer:

The degree of the zero polynomial is left undefined

Hence, option C is correct


Question 11.

Zero of the polynomial p(x) = 2x + 3 is
A.

B.

C.

D.


Answer:

We have,

p (x) = 2x + 3


So, zero of the given polynomial can be calculated as follows:


0 = 2x + 3


2x = - 3


x =


Hence, option B is correct


Question 12.

Zero of the polynomial p(x) = 2 - 5x is
A.

B.

C.

D.


Answer:

We have,

p (x) = 2 – 5x


So, zero of the given polynomial can be calculated as follows:


0 = 2 – 5x


5x = 2


x =


Hence, option A is correct


Question 13.

Zero of the zero polynomial is
A. 0

B. 1

C. every real number

D. not defined


Answer:

The zero of the zero polynomial is not defined

Hence, option D is correct


Question 14.

If p(x) = x + 4, then p(x) + (-x) =?
A. 0

B. 4

C.2x

D. 8


Answer:

We have,

p (x) = x + 4


p (-x) = - x + 4


Then, the value of p (x) + (-x) and it can be calculated as follows:


p (x) + p (-x) = x + 4 – x + 4


= 4 + 4


= 8


Hence, option D is correct


Question 15.

If then
A. 0

B. 1

C.

D. -1


Answer:

We have,

p (x) = x2 - 2x + 1



= 8 – 8 + 1


= 1


Hence, option B is correct


Question 16.

The zeroes of the polynomial p (x) = x2 + x - 6 are
A. 2, 3

B. -2, 3

C. 2, -3

D. -2, -3


Answer:

We have,

p (x) = x2 + x - 6


So, zero of the given polynomial can be calculated as follows:


x2 + x – 6 = 0


x2 + 3x – 2x – 6 = 0


x (x + 3) – 2 (x + 3) = 0


(x + 3) (x – 2) = 0


Now, x + 3 = 0


x = - 3


And, x – 2 = 0


x = 2


Hence, the zeros of the given polynomial are -3 and 2


∴ Option C is correct


Question 17.

The zeroes of the polynomial p (x) = 2x2 + 5x - 3 are
A.

B.

C.

D.


Answer:

We have,

p (x) = 2x2 + 5x - 3


So, zero of the given polynomial can be calculated as follows:


2x2 + 5x – 3 = 0


2x2 + 6x – x – 3 = 0


2x (x + 3) – 1 (x + 3) = 0


(2x – 1) (x + 3) = 0


Now, (2x – 1) = 0


2x = 1



Also, (x + 3) = 0


x = -3


Hence, zeros of the given polynomial are and – 3


∴ Option B is correct


Question 18.

If (x2+ kx – 3) = (x – 3 ) (x + 1) then k =?
A. 2

B. -2

C. 3

D. -1


Answer:

We have, (x2 + kx – 3) = (x – 3) (x + 1)

So, the value of k can be calculated as follows:


(x2 + kx – 3) = x2 – 3x + x – 3


x2 + kx – 3 = x2 – 2x – 3


On comparing the coefficients, we get,


kx = - 2x


k = - 2


Thus, the value of k = - 2


Hence, option B is correct


Question 19.

If (x + 1) is a factor of 2x2+ kx, then k =?
A. -3

B. -2

C. 2

D. 4


Answer:

Let p (x) = 2x2 + kx


It is given that, (x + 1) is a factor of (2x2 + kx)


Thus, x = -1 is a factor of (2x2 + kx)


∴ p (-1) = 0


2 (-1)2 + k (-1) = 0


2 – k = 0


k = 2


Thus, the value of k = 2


Hence, option C is correct


Question 20.

The coefficient of the highest power of x in the polynomial 2x2 – 4x4 + 5x2 – x5 + 3 is:
A. 2

B. -4

C. 3

D. -1


Answer:

We have,

2x2 – 4x4 + 5x2 – x5 + 3


From the given polynomial,


The highest power of x = 5


Coefficient of x5 = - 1


Hence, option D is correct


Question 21.

When (x31 + 31) is divided by (x + 1), the remainder is
A. 0

B. 1

C. 30

D. 31


Answer:

Let, p (x) = (x31 + 31)

And, x + 1 = 0


x = - 1


It is given that, (x + 1) is a factor of p (x) so the remainder is equal to p (-1)


∴ p (-1) = (-1)31 + 31


= - 1 + 31


= 30


Hence, option C is correct


Question 22.

When p (x) = x3 – ax2 + x is divided by (x – a), the remainder is
A. 0

B. a

C. 2a

D. 3a


Answer:

We have,

x3 – ax2 + x


Let, p (x) = x3 – ax2 + x


And, x - a = 0


x = a


It is given that, (x - a) is a factor of p (x) so the remainder is equal to p (a)


∴ p (a) = (a)3 – a (a)2 + a


= a3 – a3 + a


= a


Hence, option B is correct


Question 23.

When p (x) = (x3 + ax2 + 2x + a) is divided by (x + a), the remainder is
A. 0

B. a

C. –a

D. 2a


Answer:

We have,

(x3 + ax2 + 2x + a)


Let, p (x) = (x3 + ax2 + 2x + a)


And, x + a = 0


x = - a


It is given that, (x + a) is a factor of p (x) so the remainder is equal to p (-a)


∴ p (-a) = (-a)3 + a (-a)2 + 2 (-a) + a


= - a3 + a3 – 2a + a


= - a


Hence, option C is correct


Question 24.

When p (x) = x4 + 2x3 – 3x2 + x – 1 is divided by (x – 2), the remainder is
A. 0

B. -1

C. –15

D. 21


Answer:

We have,

x4 + 2x3 – 3x2 + x - 1


Let, p (x) = x4 + 2x3 – 3x2 + x - 1


And, x - 2 = 0


x = 2


It is given that, (x - 2) is a factor of p (x) so the remainder is equal to p (2)


∴ p (2) = (2)4 + 2 (2)3 – 3 (2)2 + 2 - 1


= 16 + 16 – 12 + 2 – 1


= 34 – 13


= 21


Hence, option D is correct


Question 25.

When p(x) = x3 - 3x2 + 4x + 32 is divided by (x + 2), the remainder is
A. 0

B. 32

C. 36

D. 4


Answer:

We have,

x3 - 3x2 + 4x + 32


Let, p (x) = x3 - 3x2 + 4x + 32


And, x + 2 = 0


x = - 2


It is given that, (x + 2) is a factor of p (x) so the remainder is equal to p (- 2)


∴ p (- 2) = (- 2)3 - 3 (- 2)2 + 4 (- 2) + 32


= - 8 - 12 – 8 + 32


= - 28 + 32


= 4


Hence, option D is correct


Question 26.

When p (x) = 4x3 - 12x2 + 11x – 5 is divided by (2x – 1), the remainder is
A. 0

B. -5

C. -2

D. 2


Answer:

We have,

4x3 - 12x2 + 11x - 5


Let, p (x) = 4x3 - 12x2 + 11x - 5


And, (2x – 1) = 0


2x = 1


x =


It is given that, (2x - 1) is a factor of p (x) so the remainder is equal to p()


∴ p (2) = 4 ()3 - 12 ()2 + 11 () - 5


= 4 × - 12 × + 11 × - 5


= - 3 + - 5


= – 8


= 6 – 8


= - 2


Hence, option C is correct


Question 27.

(x +1) is a factor of the polynomial:
A. x3 – 2x2 + x + 2

B. x3 – 2x2 + x - 2

C. x3 – 2x2 - x - 2

D. x3 – 2x2 - x + 2


Answer:

We have, (x + 1) = 0

x = - 1


Firstly, putting (x = - 1) in x3 – 2x2 + x + 2 we get:


= (- 1)3 – 2 (-1)2 + (-1) + 2


= - 1 – 2 – 1 + 2


= - 2


∴ (x + 1) is not a factor of x3 – 2x2 + x + 2


Secondly, putting (x = - 1) in x3 + 2x2 + x - 2 we get:


= (-1)3 + 2 (-1)2 + (-1) – 2


= - 1 + 2 – 1 – 2


= - 2


∴ (x + 1) is not a factor of x3 + 2x2 + x – 2


Thirdly, putting (x = - 1) in x3 + 2x2 – x – 2 we get:


= (-1)3 + 2 (-1)2 – (-1) – 2


= - 1 + 2 + 1 – 2


= 0


Hence, (x + 1) is a factor of x3 + 2x2 + x – 2


Thus, option C is correct


Question 28.

4x2 + 4x – 3 = ?
A. (2x – 1) (2x - 3)

B. (2x + 1) (2x - 3)

C. (2x – 1) (2x + 3)

D. none of these


Answer:

We have,

4x2 + 4x – 3


= 4x2 – 2x + 6x – 3


= 2x (2x – 1) + 3 (2x – 1)


= (2x – 1) (2x + 3)


Hence, option D is correct


Question 29.

6x2 + 17x + 5
A. (2x - 1) (3x + 5)

B. (2x + 5) (3x - 1)

C. (6x + 5) (x + 1)

D. none of these


Answer:

We have,

6x2 + 17x + 5


= 6x2 + 2x + 15x + 5


= 2x (3x + 1) + 5 (3x + 1)


= (2x + 5) (3x + 1)


Hence, option D is correct


Question 30.

x2 - 4x – 21 = ?
A. (x - 3) (x - 7)

B. (x - 3) (x + 7)

C. (x + 3) (x - 7)

D. none of these


Answer:

We have,

x2 - 4x – 21


= x2 + 3x - 7x – 21


= x (x + 3) - 7 (x + 3)


= (x + 3) (x - 7)


Hence, option C is correct


Question 31.

If (x + 5) is a factor of p (x) = x3 – 20x + 5k, then k =?
A. -5

B. 5

C. 3

D. -3


Answer:

We have,

p (x) = x3 – 20x + 5k


It is given in the question that, (x + 5) is a factor of p (x) so:


p (- 5) = 0


(- 5)3 – 20 (- 5) + 5 k = 0


- 125 + 100 + 5k = 0


- 25 + 5k = 0


5k = 25


k =


k = 5


Hence, option B is correct


Question 32.

3x3 + 2x2 + 3x + 2 = ?
A. (3x - 2) (x2 - 1)

B. (3x -2 )(x2 + 1)

C. (3x +2) (x2 - 1)

D. (3x+2) (x2 + 1)


Answer:

We have,

3x3 + 2x2 + 3x + 2


= x2 (3x + 2) + 1 (3x + 2)


= (x2 + 1) (3x + 2)


Hence, option D is correct


Question 33.

If where and then the value of is
A. 1

B. -1

C. 0

D.


Answer:

We have,


= - 1


x2 + y2 = - xy


x2 + y2 + xy = 0


∴ Value of (x3 – y3) = (x – y) (x2 + y2 + xy)


= (x - y) × 0


= 0


Hence, option C is correct


Question 34.

If a + b + c = 0, then a3 + b3 + c3 = ?
A. 0

B. abc

C. 2abc

D. 3abc


Answer:

The correct answer is D


It is given that: a + b + c = 0


We know,


(a + b + c)3 = a3 + b3 + c3 + 2(ab + bc + ac)(a + b + c)


Put a + b + c = 0 in the above equation we get,


Then, a3 + b3 + c3 = 3 abc


Hence, option D is correct


Question 35.

(x + 2) and (x – 1) are factors of (x3 + 10x2 + mx + n) then
A. m = 5, n = -3

B. m = 7, n = -18

C. m = 17, n = -8

D. m = 23, n = -19


Answer:

We have,

(x3 + 10x2mx + n)


Let, p (x) = x3 + 10x2 + mx + n


It is given in the question that (x + 2) and (x – 1) are the factors of p (x)


∴ p (-2) = 0


(-2)3 + 10 (-2)2 + m (-2) + n = 0


- 8 + 40 – 2m + n = 0


32 – 2m + n = 0


2m – n – 32 = 0 ……….(i)


And,


p (1) = 0


(1)3+ 10 (1)2 + m (1) n


1 + 10 + m + n = 0


11 + m + n = 0


m + n + 11 = 0 ………. (ii)


Now, adding equation (i) and (ii) we get


2m – n - 32 + m + n + 11 = 0


3m - 21 = 0


3m = 21


m =


m = 7


Now, putting the value of m in (ii) we get:


7 + n + 11 = 0


18 + n = 0


n = - 18


∴ the value of m is 7 and that of n is – 18


Hence, option B is correct


Question 36.

The value of (369)2 – (368)2 = ?
A.

B. 81

C. 37

D. 737


Answer:

We have,

(369)2 – (368)2


We know that,


(a2 – b2) = (a+ b) (a – b)


Using this identity, we get:


(369)2 – (368)2 = (369 + 368) (369 – 368)


= 737 × 1


= 737


Hence, option D is correct


Question 37.

104 x 96 =?
A. 9894

B. 9984

C. 9684

D. 9884


Answer:

We have,

104 × 96 = (100 + 4) (100 – 4)


= (100)2 – (4)2


= 10000 – 16


= 9984


Hence, option B is correct


Question 38.

4a2 + b2 + 4ab + 8a + 4b + 4 = ?
A. (2a + b + 2)2

B. (2a - b + 2)2

C. (a + 2b + 2)2

D. none of these


Answer:

We have,

4a2 + b2 + 4ab + 8a + 4b + 4


We know that,


x2 + y2 + z2 + 2xy + 2yz + 2xz = (x + y + z)2


= (2a)2 + (b)2 + (2)2 + 2 (2a) (b) + 2 (b) (2) + 2 × 2 (2a)


= (2a + b + 2)2


Hence, option A is correct


Question 39.

The coefficient of x in the expansion of (x + 3)3 is
A. 1

B. 9

C. 18

D. 27


Answer:

The coefficient of x in the expansion of (x+3)2 can be calculated as follows:

(x + 3)3 = x3 + (3)3 + 3 (x) (3) (x + 3)


= x3 + 27 + 9x (x + 3)


= x3 + 27 + 9x2 + 27x


∴ Coefficient of x is 27


Hence, option D is correct


Question 40.

If a + b + c = 0, then
A. 1

B. 0

C. -1

D. 3


Answer:

It is given in the question that,

a + b + c = 0


So,



= 3


Hence, option D is correct


Question 41.

If x + y + z = 9 and xy + yz + zx = 23, then the value of (x3 + y3 + z3 – 3xyz) = ?
A. 108

B. 207

C. 669

D. 729


Answer:

It is given that,

x + y + z = 9


And, xy + yz + zx = 23


As we know that,


(x + y + z)2 = (x2 + y2 + z2 + 2xy + 2yz + 2zx)


∴ (9)2 = [x2 + y2 + z2 + 2 (xy + yz + zx)]


x2 + y2 + z2 = 81 – 2 × 23


x2 + y2 + z2 = 81 – 46


x2 + y2 + z2 = 35


We also know that:


(x3 + y3 + z3 – 3xyz) = (x + y + z) [x2 + y2 + z2 – (xy + yz + zx)]


= 9 (35 – 23)


= 9 × 12


= 108


Hence, option A is correct


Question 42.

If (x100 + 2x99 + k) is divisible by (x + 1), then the value of k is
A. 1

B. 2

C. -2

D. -3


Answer:

Let p (x) = x100 + 2x99 + k

It is given in the question that, (x + 1) is divisible by (x + 1)


So, p (-1) = 0


(-1)100 + 2 (-1)99 + k = 0


1 + 2 (-1) + k = 0


1 – 2 + k = 0


- 1 + k = 0


k = 1


Thus, the value of k = 1


Hence, option A is correct


Question 43.

In a polynomial in x, the indices of x must be
A. Integers

B. Positive integers

C. Non-negative integers

D. Real numbers


Answer:

We know that,

In any polynomial in x, the indices of x must be a non-negative integer


Hence, option C is correct


Question 44.

For what value of k is the polynomial p (x) = 2x3 – kx2 + 3x + 10 exactly divisible by (x + 2)?
A.

B.

C. 3

D. -3


Answer:

We have,

p (x) = 2x3 – kx2 + 3x + 10


It is given in the question that (x + 2) is exactly divisible by p (x)


∴ p (-2) = 0


2 (-2)3 – k (-2)2 + 3 (-2) + 10 = 0


2 × (-8) – k × (4) – 6 + 10 = 0


- 16 – 4k – 6 + 10 = 0


- 22 – 4k + 10 = 0


- 12 – 4k = 0


- 12 = 4k


k =


k = - 3


Hence, option D is correct


Question 45.

207 x 193 =?
A. 39851

B. 39951

C. 39961

D. 38951


Answer:

We have,

207 × 193 = (200 + 7) (200 – 7)


= (200)2 – (7)2


= 40000 – 49


= 39951


Hence, option B is correct


Question 46.

305 x 308 =?
A. 94940

B. 93840

C. 93940

D. 94840


Answer:

We have,

305 × 308 = 305 × (300 + 8)


= 305 × 300 + 305 × 8


= 91500 + 2440


= 93940


Hence, option C is correct


Question 47.

The zeroes of the polynomial p (x) = x2 – 3x are
A. 0, 0

B. 0, 3

C. 0, -3

D. 3, -3


Answer:

We have,

p (x) = x2 – 3x


∴ Zeros of p (x) are:


p (x) = 0


x2 – 3x = 0


x (x – 3) = 0


So, x = 0


And, x – 3 = 0


x = 3


Thus, zeros of the given polynomial are 0 and 3


Hence, option B is correct


Question 48.

The zeroes of the polynomial p (x) = 3x2 – 1 are
A.

B.

C.

D.


Answer:

We have,

p (x) = 3x2 – 1


∴ Zeros of p (x) are:


p (x) = 0


3x2 – 1 = 0


3x2 = 1


So, x2 =


And, x =


Thus, zeros of the given polynomial are and -


Hence, option D is correct


Question 49.

The question consists of two statements, namely, Assertion (A) and Reason (R), Please select the correct answer.

A. Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).

B. Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct ex

C. Assertion (A) is true and Reason (R) is false.

D. Assertion (A) is false and Reason (R) is true.


Answer:

The correct answer is: (a)

We have,


p (x) = x2 + kx + 1


(x – 1) is a factor of p (x)


∴ p (1) = 0


(1)2 + k (1) + 1 = 0


1 + k + 1 = 0


2 + k = 0


k = - 2


Hence, both Assertion (A) and Reason (R) are true also Reason (R) is the correct explanation of Assertion (A)


∴ Option A is correct


Question 50.

The question consists of two statements, namely, Assertion (A) and Reason (R), Please select the correct answer.

A. Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).

B. Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct ex

C. Assertion (A) is true and Reason (R) is false.

D. Assertion (A) is false and Reason (R) is true.


Answer:

We have,

p (x) = x3 – ax2 + 6x - a


(x – a) is divided by p (x)


∴ p (a) = (a)3 – a (a)2 + 6 (a) - a


= a3 – a3 + 6a - a


= 5a


Hence, both Assertion (A) and Reason (R) are true also Reason (R) is the correct explanation of Assertion (A)


∴ Option A is correct


Question 51.

The question consists of two statements, namely, Assertion (A) and Reason (R), Please select the correct answer.

A. Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).

B. Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct ex

C. Assertion (A) is true and Reason (R) is false.

D. Assertion (A) is false and Reason (R) is true.


Answer:

The correct answer is: (B)

We have,


p (x) = x3 – 2x + 3k


(x – 2) is a factor of p (x)


∴ p (2) = 0


(2)3 – 2 (2) + 3k = 0


8 – 4 + 3k = 0


4 + 3k = 0


3k = - 4


k =


Hence, both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)


∴ Option B is correct


Question 52.

The question consists of two statements, namely, Assertion (A) and Reason (R), Please select the correct answer.

A. Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A).

B. Both Assertion (A) and Reason (R) are true but Reason (R) is not a correct ex

C. Assertion (A) is true and Reason (R) is false.

D. Assertion (A) is false and Reason (R) is true.


Answer:

The correct answer is: (a)

We have,


(25)3 + (-16)3 + (-9)3


Since, 25 – 16 – 9 = 25 – 25


= 0


∴ 3 (-25) (-16) (-9)


= 75 × 144


= 10800


Hence, both Assertion (A) and Reason (R) are true also Reason (R) is the correct explanation of Assertion (A)


∴ Option A is correct


Question 53.

Match the following columns:


The correct answer is:

(a)-……., (b)-……., (c)-……., (d)-…….,


Answer:

The correct match for the above is as follows:



Hence, the correct answer is:


(a) – (r)


(b) – (p)


(c) – (s)


(d) – (q)



Question 54.

Match the following columns:


The correct answer is:

(a)-……., (b)-……., (c)-……., (d)-…….,


Answer:

The correct match for the above is as follows:



Hence, the correct answer is:


(a) – (r)


(b) – (p)


(c) – (s)


(d) – (q)




Formative Assessment (unit Test)
Question 1.

Let Find p(-2).


Answer:

We have,

p (x) = 3x3 + 4x2 – 5x + 8


So, p (-2) = 3 (-2)3 + 4 (-2)2 – 5 (-2) + 8


= 3 × -8 + 4 × 4 + 10 + 8


= - 24 + 16 + 10 + 8


= - 24 + 34


= 10



Question 2.

Find the remainder when p (x) = 4x3 + 8x2 – 17x + 10 is divided by (2x – 1).


Answer:

We have,

p (x) = 4x3 + 8x2 – 17x + 10


Also, 2x – 1 = 0


2x = 1


x =


∴ p () = 4 ()3 + 8 ()2 – 17 () + 10


= 4 × + 8 × - 17 × + 10


= + 2 – + 10


= + 12


= + 12


= - 8 + 12


= 4


Hence, remainder = 4



Question 3.

If (x – 2) is a factor of 2x3 – 7x2 + 11x + 5a, find the value of a.


Answer:

It is given in the question that (x – 2) is a factor of 2x3 – 7x2 + 11x + 5a

Let f (x) = 2x3 – 7x2 + 11x + 5a


Now, x – 2 = 0


x = 2


∴ f (2) = 0


2 (2)3 – 7 (2)2 + 11 (2) + 5a = 0


16 – 28 + 22 + 5a = 0


38 – 28 + 5a = 0


10 + 5a = 0


5a = - 10


a =


a = - 2


Hence, the value of a = - 2



Question 4.

For what value of m, p(x) = (x3 – 2mx2 + 16) is divisible by (x + 2)?


Answer:

It is given in the question that (x + 2) is a factor of x3 – 2mx2 + 16

p (x) = x3 – 2mx2 + 16


Now, x + 2 = 0


x = - 2


∴ f (-2) = 0


(- 2)3 – 2m (- 2)2 + 16 = 0


- 8 – 8m + 16 = 0


- 8 + 8m = 0


- 8 = - 8m


m =


m = 1


Hence, the value of m = 1



Question 5.

If (a + b + c) = 8 and (ab + bc + ca) = 19, find (a2 + b2 + c2)


Answer:

It is given in the question that,

(a + b + c) = 8


And, (ab + bc + ca) = 19


We know that,


(a + b + c)2 = a2 + b2 + c2 + 2 (ab + bc + ca)


∴ (8)2 = a2 + b2 + c2 + 2 × 19


64 = a2 + b2 + c2 + 38


64 – 38 = a2 + b2 + c2


a2 + b2 + c2 = 26



Question 6.

Expand: (3a + 4b + 5c)2.


Answer:

We have,

(3a + 4b + 5c)2


We know that,


(a + b + c)2 = a2 + y2 + c2 + 2 (xy + yz + zx)


∴ (3a + 4b + 5c)2 = (9a2 + 16b2 + 25c2 + 2 × 3a × 4b + 2 × 4b × 5c + 2 × 5c × 3a)


= 9a2 + 16b2 + 25c2 + 24ab + 40bc + 30ac



Question 7.

Expand: (3x + 2)2.


Answer:

We have,

(3x + 2)2


We know that,


(a + b)3 = a3 + b3 + 3ab (a + b)


∴ (3x + 2)2 = (3x)3 + (2)3 + 3 (3x) (2) (3x + 2)


= 27x3 + 8 + 18x (3x + 2)


= 27x3 + 8 + 54x2 + 36x


= 27x3 + 54x2 + 36x + 8



Question 8.

Evaluate: {(28)3 + (-15)3 + (-13)3}.


Answer:

We have,

[(28)3 + (-15)3 + (-13)3]


Now putting a = 28, b = - 15 and c = - 13


Now, a + b + c = 28 – 15 – 13


= 28 – 28


= 0


So, x3 + y3 + z3 = 3xyz


(28)3 + (-15)3 + (-13)3 = 3 × (28) × (-15) × (-13)


= 84 × 195


= 16380



Question 9.

If (x60 + 60) is divided by (x + 1), the remainder is
A. 0

B. 59

C. 61

D. 2


Answer:

It is given in the question that (x + 1) is divided by (x60 + 60)

Let f (x) = x60 + 60


And, (x + 1) = 0


x = - 1


∴ f (x) = x60 + 60


f (-1) = (-1)60 + 60


= 1 + 60


= 61


Hence, remainder = 61


Thus, option C is correct


Question 10.

One of the factors of (36x2 – 1) + (1 + 6x)2 is
A. (6x – 1)

B. (6x + 1)

C. 6x

D. 6-x


Answer:

We have,

(36x2 – 1) + (1 + 6x)2


= [(6x)2 – (1)2] + (1 + 6x)2


= (6x – 1) (6x + 1) + (6x + 1) (6x + 1)


= (6x + 1) (6x – 1 + 1 + 6x)


= (6x + 1) (12x)


∴ (6x + 1) is a factor of (36x2 – 1) + (6x + 1)2


Hence, option B is correct


Question 11.

If then (a3 – b3) = ?
A. -1

B. -3

C. -2

D. 0


Answer:

It is given in the question that,



a2 + b2 = - ab


a2 + b2 + ab = 0 (i)


We know that,


a3 – b3 = (a – b) (a2 + b2 + ab)


From (i), we have a2 + b2 + ab = 0


∴ a3 – b3 = (a – b) × 0


a3 – b3 = 0


Hence, option D is correct


Question 12.

The coefficient of x in the expansion of (x + 5)3 is
A. 1

B. 15

C. 45

D. 75


Answer:

We have,

(x + 5)3 = x3 + (5)3 + 3 × x × 5 (x + 5)


= x3 + 125 + 15x (x + 5)


= x3 + 125 + 15x2 + 75x


∴ Coefficient of x = 75


Hence, option D is correct


Question 13.

is a polynomial of degree
A.

B. 2

C. 0

D. 1


Answer:

We know that,

is a polynomial of degree 0


Hence, option C is correct


Question 14.

One of the zeroes of the polynomial 2x2 + 7x – 4 is
A. 2

B.

C. -2

D.


Answer:

Let f(x) = 2x2 + 7x – 4

= 2x2 + 8x – x – 4


= 2x (x + 4) – 1 (x + 4)


= (2x – 1) (x + 4)


So, 2x – 1 = 0


2x = 1


x =


And, x + 4 = 0


x = - 4


Thus, one of zero of the given polynomial is


Hence, option B is correct


Question 15.

Zero of the zero polynomial is
A. 0

B. 1

C. every real number

D. not defined


Answer:

We know that,

The zero of the zero polynomial is not defined


Hence, option D is correct


Question 16.

If (x + 1) and (x – 1) are factors of p (x) = ax3 + x2 – 2x + b, find the values of a and b.


Answer:

We have,

p (x) = ax3 + x2 – 2x + b


It is given in the question that,


(x + 1) and (x – 1) are the factors of p (x)


∴ p (-1) = p (1)


So, p (-1) = a (-1)3 + (-1)2 – 2 (-1) + b


0 = - a + 1 + 2 + b


0 = - a + 3 + b (i)


Also, p (1) = a (1)3 + (1)2 – 2 (1) + b


0 = a + 1 – 2 + b


0 = a + b – 1 (ii)


As, p (-1) = p (1)


- a + 3 + b = a + b - 1


- 2a = - 4


a = 2


Now, putting the value of a in (ii), we get:


2 + b – 1 = 0


1 + b = 0


b = - 1


Hence, the value of a is 2 and that of b is -1



Question 17.

If (x + 2) is a factor of p (x) = ax3 + bx2 + x – 6 and p(x) when divided by (x – 2) leaves a remainder 4, prove that a = 0 and b = 2.


Answer:

We have,

p (x) = ax3 + bx2 + x – 6


It is given in the question that, (x + 1) is a factor of p (x)


x + 2 = 0


x = - 2


∴ f (-2) = 0


a (-2)3 + b (-2)2 + (-2) – 6 = 0


- 8a + 4b – 2 – 6 = 0


- 8a + 4b – 8 = 0


- 4 (2a – b + 2) = 0


2a – b + 2 = 0 (i)


Also, it is given in the question that when p (x) is divided by (x – 2) then it leaves a remainder 4


∴ p (2) = 4


a (2)3 + b (2)2 + (2) – 6 = 4


8a + 4b + 2 – 6 = 4


8a + 4b – 4 - 4= 0


4 (2a + b – 2) = 0


2a + b – 2 = 0 (ii)


Now, adding (i) and (ii) we get:


2a – b + 2 + 2a + b – 2 = 0


4a = 0


a = 0


Putting the value of a in (ii), we get:


2 (0) + b – 2 = 0


b – 2 = 0


b = 2


Hence, it is proved that the value of a is 0 and that of b is 2



Question 18.

The expanded form of (3x – 5)3 is
A.

B.

C.

D. none of these


Answer:

We have,

(3x – 5)3 = (3x)3 – (5)3 – 3 (3x) (5) (3x – 5)


= 27x3 – 125 – 45x (3x – 5)


= 27x3 - 125 – 135x2 + 225x


= 27x3 – 135x2 + 225x - 125


Hence, option D is correct


Question 19.

If a + b + c = 5 and ab + bc + ca = 10, prove that a3 + b3 + c3 – 3abc = – 25.


Answer:

It is given in the question that,

a + b + c = 5


And, ab + bc + ca = 0


We know that,


(a + b + c)2 = a2 + b2 + c2 + 2 (ab + bc + ca)


Putting the given values, we get:


(5)2 = a2 + b2 + c2 + 20


25 – 20 = a2 + b2 + c2


a2 + b2 + c2 = 5 (i)


Also, we know that


(a3 + b3 + c3 – 3abc) = (a + b + c) (a2 + b2 + c2 – ab – bc – ca)


= (a + b + c) [(a2 + b2 + c2) – (ab + bc + ca)]


Now, putting the values we get:


= (5) × (5 – 10)


= 5 × (-5)


= - 25


Hence, it is proved that


(a3 + b3 + c3 – 3abc) = - 25



Question 20.

If p (x) = 2x3 + ax2 + 3x – 5 and q (x) = x3 + x2 – 4x + a leave the same remainder when divided by (x – 2), show that


Answer:

We have,

p (x) = 2x3 + ax2 + 3x – 5


q (x) = x3 + x2 – 4x + a


It is given in the question that, when p (x) and q (x) is divided by (x – 2) it leaves same remainder


∴ p (2) = q (2)


2 (2)3 + a (2)2 + 3 (2) – 5 = (2)3 + (2)2 – 4 (2) + a


2 × 8 + a × 4 + 3 × 2 – 5 = 8 + 4 – 4 × 2 + a


16 + 4a + 6 – 5 = 12 – 8 + a


16 + 4a + 1 = 4 + a


4a – a = 4 – 17


3a = - 13


a =


Hence proved




Exercise 2b
Question 1.

Iffind

(i) p (0)

(ii)p(3)

(iii) p(-2)


Answer:

(i) We have,



Now,


Put x = 0


p(0) = 5 - 4(0) + 2(0)2


= 5 - 4(0) + 2(0)


= 5 – 0 + 0


= 5


Hence,


P(0) = 5


(ii) We have,



Now,


Put x = 3


p(3) = 5 - 4(3) + 2(3)2


= 5 - 4(3) + 2(9)


= 5 – 12 + 18


= 11


Hence,


P (3) = 11


(iii) We have,



Now,


Put x = -2



= 5 - 4(-2) + 2(4)


= 5 + 8 + 8


= 21


Hence,


P (-2) = 21



Question 2.

If find

(i) P(0)

(ii) p(2)

(iii) p(-1)


Answer:

(i) We have,



Now,


Put y = 0



= 4 - 3(0) - (0) + 5(0)


= 4 – 0 – 0 + 0


= 4


Hence,


P (0) = 4


(ii) We have,



Now,


Put y = 2


23


=


=


=


Hence,


P (2) = 46


(iii) We have,



Now,


Put y = -1


23


=


=


=


Hence,


p(-1) = -5



Question 3.

If find

(i) f (0)

(ii) f (4)

(iii) f (-5)


Answer:

(i) We have,



Now,


Put t = 0


f(0) = 4(0)2 - 3(0) + 6


= 4(0) - 3(0) + 6


= 0 – 0 + 6


= 6


Hence,


f(0) = 6


(ii) We have,



Now,


Put t = 4


f(4) = 4(4)2 -3(4) + 6


= 4(16) - 3(4) + 6


= 64 – 12 + 6


= 58


Hence,


f(4) = 58


(iii) We have,



Now,


Put t = -5


f(-5)=4(-5)2 - 3(-5) + 6


= 4(25) - 3(-5) + 6


= 100 + 15 + 6


= 121


Hence,


f(0) = 6



Question 4.

Find the zero of the polynomial:

(i) P(x)=x-5

(ii) q(x)=x+4

(iii) p(t)=2t-3

(iv) f(x)=3x+1

(v) g(x)=5-4x

(vi) h(x)=6x-1

(vii) p(x)=ax + b,a≠0

(viii) q(x) = 4x

(ix) p(x)=ax,a≠0


Answer:

(i) At first,


In order to find the zero of the polynomial we will,


Put p(x) = 0


Now,


We have,


P(x)=x-5


0 = x – 5


x = 5


Hence, 5 is the zero of the given polynomial.


(ii) At first,


In order to find the zero of the polynomial we will,


Put q(x) = 0


Now,


We have,


q(x)=x+4


0 = x + 4


x = - 4


Hence, -4 is the zero of the given polynomial.


(iii) At first,


In order to find the zero of the polynomial we will,


Put p(t) = 0


Now,


We have,


P(t)= 2t - 3


0 = 2t – 3


2t = 3


t = 3/2


Hence, 3/2 is the zero of the given polynomial.


(iv) At first,


In order to find the zero of the polynomial we will,


Put f(x) = 0


Now,


We have,


f(x)= 3x + 1


0 = 3x + 1


3x = -1


x =


Hence, -1/3 is the zero of the given polynomial.


(v) At first,


In order to find the zero of the polynomial we will,


Put g(x) = 0


Now,


We have,


g(x)= 5 – 4x


0 = 5 – 4x


4x = 5


x = 5/4


Hence, 5/4 is the zero of the given polynomial.


(vi) At first,


In order to find the zero of the polynomial we will,


Put h(x) = 6x - 1


Now,


We have,


h(x)= 6x- 1


0 = 6x – 1


6x = 1


x = 1/6


Hence, 1/6 is the zero of the given polynomial.


(vii) At first,


In order to find the zero of the polynomial we will,


Put p(x) = 0


Now,


We have,


p(x)= ax + b


0 = ax + b


ax = -b


x = (-b)/a


Hence, (-b)/a is the zero of the given polynomial.


(viii) At first,


In order to find the zero of the polynomial we will,


Put q(x) = 0


Now,


We have,


q(x)= 4x


0 = 4x


x = 0


Hence, 0 is the zero of the given polynomial.


(ix) At first,


In order to find the zero of the polynomial we will,


Put p(x) = 0


Now,


We have,


p(x)= ax


0 = ax


x = 0


Hence, 0 is the zero of the given polynomial.



Question 5.

Verify that:
(i) 4 is a zero of the polynomial p(x)=x-4.
(ii) -3 is a zero of the polynomial p(x) = x + 3.
(iii) -1/2 is a zero of the polynomial p(y)=2y+1.
(iv) 2/5 is a zero of the polynomial p(x) =2-5x.
(v) 1 and 2 are the zeros of the polynomial p(x)=(x-1)(x-2)
(vi) 0 and 3 are the zeros of the polynomial p(x) =x2 - 3x
(vii) 2 and-3 are the zeros of the polynomial p(x) =x2 + x - 6


Answer:

(i) We have, p(x) = x – 4

In order to verify the zero of the polynomial,
Put p(x) = 4
put x = 4 in the expression , we get,
p(4) = 4 – 4
p(4) = 0
Since p(4) = 0

Hence, 4 is a zero of the polynomial p(x).

(ii) We have, p(x) = x + 3

In order to verify the zero of the polynomial,
Put p(x) = -3
p(-3) = - 3 + 3
p(-3) = 0
Since p(-3) = 0

Hence, -3 is a zero of the polynomial p(x).

(iii) We have, p(y) = 2y + 1

In order to verify the zero of the polynomial,
Put p(y) = 1/2

p(1/2) = 2(1/2) + 1

p(1/2) = 1 + 1
p(1/2) = 2

Since p(1/2) ≠ 0

Hence, 1/2 is not a zero of the polynomial p(y)

(iv) We have, p(x) = 2 - 5x

In order to verify the zero of the polynomial,
Put p(x) = 2/5
p(2/5) = 2 - 5 (2/5)
p(2/5)= 2 - 2
p(2/5)= 0

Since p(2/5) = 0

Hence, 2/5 is a zero of the polynomial p(x)

(v) We have, p(x) = (x-1)(x-2)

In order to verify the zero of the polynomial,

Case 1: Put x = 1, we get,

p(1) = (1-1)(1-2)
p(1) = 0(-1)
p(1) = 0
Hence, 1 is a zero of the polynomial p(x)

Case 2: Put x = 2, we get,

p(3) = (2-1)(2-2)
p(3) = (1)0
p(3) = 0
since p(3) = 0
Hence, 2 is a zero of the polynomial p(x)

(vi) We have, p(x) = x2 -3x
In order to verify the zero of the polynomial,

Case 1: Put x = 0

p(0) = (0)2 – 3(0)
p(0) = 0 - 0
p(0) = 0

Since p(0) = 0
Hence, 0 is a zero of the polynomial p(x)

Case 2: Put x = 3
p(3) = (3)2 – 3(3)
p(3) = 9 - 9
p(3) = 0

Since p(3) = 0
Hence, 3 is a zero of the polynomial p(x)

(vii) We have, p(x) =x2 + x - 6

In order to verify the zero of the polynomial,

Case 1: Put x = 2
p(2) = (2)2 + 2 - 6
p(2) = 4 + 2 - 6
p(2) = 0

Since p(2) = 0

Hence, 2 is a zero of the polynomial p(x)

Case 2: Put x = -3

p(3) = (-3)2 + (–3) – 6
p(3) = 9 - 3 - 6
p(3) = 0

Since p(-3) = 0

Hence, -3 is a zero of the polynomial p(x)



Exercise 2c
Question 1.

is divided by (x-1)


Answer:

Let, f(x) = x3 – 6x2 + 9x + 3


Now,


As per the question,


x – 1 = 0


x = 1


Using Remainder theorem,


We know that when f(x)is divided by (x – 1), the remainder so obtained will be f(1).


Hence,


f(1) = (1)3 – 6(1)2 + 9(1) + 3


= 1 – 6 + 9 + 3


= 13 – 6


= 7


Therefore,


The required remainder is 7



Question 2.

is divided by (x-3)


Answer:

Let, f(x) = 2x3 – 5x2 + 9x - 8


Now,


As per the question,


x – 3 = 0


x = 3


Using Remainder theorem,


We know that when f(x)is divided by (x – 3), the remainder so obtained will be f(3).


Hence,


f(3) = 2(3)3 – 5(3)2 + 9(3) - 8


= 2(27) – 5(9) + 27 - 8


= 54 – 45 + 19


= 28


Therefore,


The required remainder is 28



Question 3.

is divided by (x-2)


Answer:

Let, f(x) = 3x4 – 6x2 - 8x + 2


Now,


As per the question,


x – 2 = 0


x = 2


Using Remainder theorem,


We know that when f(x)is divided by (x – 2), the remainder so obtained will be f(2).


Hence,


f(2) = 3(2)4 – 6(2)2 - 8(2) + 2


= 3(16) – 6(4) -16 + 2


= 48 -24 – 14


= 10


Therefore,


The required remainder is 10.



Question 4.

is divided by (x-6)


Answer:

Let, f(x) = x3 – 7x2 + 6x + 4


Now,


As per the question,


x – 6 = 0


x = 6


Using Remainder theorem,


We know that when f(x) is divided by (x – 6), the remainder so obtained will be f(6).


Hence,


f(6) = (6)3 – 7(6)2 + 6(6) + 4


= (216) – 7(36) + 36 + 4


= 256 -252


= 4


Therefore,


The required remainder is 4.



Question 5.

is divided by (x+2)


Answer:

Let, f(x) = x3 – 6x2 + 13x + 60


Now,


As per the question,


x + 2 = 0


x = -2


Using Remainder theorem,


We know that when f(x)is divided by (x + 2), the remainder so obtained will be f(-2).


Hence,


f(-2) = (-2)3 – 6(-2)2 + 13(-2) + 60


= - 8 – 6(4) - 26 + 60


= 60 - 58


= 2


Therefore,


The required remainder is 2.



Question 6.

is divided by (x+3)


Answer:

Let, f(x) = 2x4 + 6x3 + 2x2 + x - 8


Now,


As per the question,


x - 3 = 0


x = 3


Using Remainder theorem,


We know that when f(x)is divided by (x – 3), the remainder so obtained will be f(3).


Hence,


f(3) = 2(3)4 + 6(3)3 + 2(3)2 + 3 - 8


= 2(81) + 6(27) +18 – 5


= 18 - 11


= 7


Therefore,


The required remainder is 7.



Question 7.

is divided by (2x-1)


Answer:

Let, f(x) = 4x3 – 12x2 + 11x -5


Now,


As per the question,


2x – 1 = 0


2x = 1


x =


Using Remainder theorem,


We know that when f(x)is divided by (2x – 1), the remainder so obtained will be .


Hence,




= -4/2


= -2


Therefore,


The required remainder is -2.



Question 8.

is divided by (3x+2)


Answer:

Let, f(x) = 81x4 + 54x3 – 9x2 - 3x + 2


Now,


As per the question,


3x + 2 = 0


3x = -2


x =


Using Remainder theorem,


We know that when f(x)is divided by (2x – 1), the remainder so obtained will be .


Hence,




= 16 – 16 + 4 - 4


= 0


Therefore,


The required remainder is 0.



Question 9.

is divided by (x-a)


Answer:

Let, f(x) = x3 - ax2 + 2x - a


Now,


As per the question,


x - a = 0


x = a


Using Remainder theorem,


We know that when f(x)is divided by (x – a), the remainder so obtained will be f(a).


Hence,


f(a) = a3 – a(a)2 + 2(a) – a


= a3 – a3 + 2a – a


= 2a - a


= a


Therefore,


The required remainder is a.



Question 10.

The polynomials and when divided by (x-4) leave the same remainder. Find the value of a.


Answer:

Let f(x) = ax3 + 3x2 – 3


And,


g(x) = 2x3 - 5x + a


Now,


f(4) = a(4)3 + 3(4)2 – 3


= 64a + 48 - 3


= 64a + 45


And,


g(4) = 2(4)3 – 5(4) + a


= 128 – 20 + a


= 108 + a


According to the question,


f(4) = g(4)


64a + 45 = 108 + a


64a – a = 108 – 45


63a = 63


a = 1


Hence, the value of ‘a’ is 1.



Question 11.

The Polynomial f(x) = x4 -2x3 +3x2 -ax + b when divided by (x-1) and (x+1) leaves the remainders 5 and 19 respectively. Find the values of a and b. Hence, find the remainder when f(x) is divided by (x-2).


Answer:

Let f(x) = x4 – 2x3 + 3x2 – ax + b

Now,

f(1) = 14 – 2(1)3 + 3(1)2 – a(1) + b

5 = 1 – 2 + 3 – a + b

3 = - a + b (i)

And,

f(-1) = (-1)4 – 2(-1)3 + 3(-1)2 – a(-1) + b

19 = 1 + 2 + 3 + a + b

13 = a + b (ii)

Now,

Adding (i) and (ii),

8 + 2b = 24

2b = 16

b = 8

Now,

Using the value of b in (i)

3 = - a + 8

a = 5

Hence,

a = 5 and b = 8

Hence,

f(x) = x4 – 2(x)3 + 3(x)2 – a(x) + b

= x4 – 2x3 + 3x2 – 5x + 8

f(2) = (2)4 – 2(2)3 + 3(2)2 – 5(2) + 8

= 16 – 16 + 12 – 10 + 8

= 20 – 10

= 10

Therefore, remainder is 10



Exercise 2d
Question 1.

(x-2) is a factor of


Answer:

From the factor theorem, we have


(x – 2) is the factor of f(x) if f(2) = 0


Here, we have


f(2) = (2)3 – 8


= 8 – 8


= 0


Therefore,


(x – 2) is a factor of (x3 – 8)



Question 2.

(x-3) is a factor of


Answer:

From the factor theorem, we have


(x – 3) is the factor of f(x) if f(3) = 0


Here, we have


f(3) = 2 × 33 + 7 × 32 – 24 × 3 - 45


= 54 + 63 – 72 – 45


= 117 – 117


= 0


Therefore,


(x – 3) is a factor of (2x3 + 7x2 – 24x – 45)



Question 3.

(x-1) is a factor of


Answer:

From the factor theorem, we have


(x – 1) is the factor of f(x) if f(1) = 0


Here, we have


f(1) = 2 × 14 + 9 × 13 + 6 × 12 – 11 × 1 – 6


= 2 + 9 + 6 – 11 – 6


= 17 – 17


= 0


Therefore,


(x – 1) is the factor of (2x4 + 9x3 + 6x2 – 11x – 6)



Question 4.

(x+2) is a factor of


Answer:

From the factor theorem, we have


(x + 2) is the factor of f(x) if (f-2) = 0


Here, we have


f(-2) = (-2)4 – (-2)2 – 12


= 16 – 4 – 12


= 16 – 16


= 0


Therefore,


(x + 2) is a factor of (x4 – x2 – 12)



Question 5.

(x+5) is a factor of


Answer:

From the factor theorem, we have


(x + 5) is the factor of f(x) if f(-5) = 0


Here, we have


f(-5) = 2(-5)3 + 9(-5)2 – 11(-5) – 30


= -250 + 225 + 55 – 30


= -280 + 280


= 0


Therefore,


(x + 5) is the factor of (2x3 + 9x2 – 11x – 30)



Question 6.

(2x-3) is a factor of


Answer:

From the factor theorem, we have


(x – a) is the factor of f(x) if f(a) = 0


Here, we have


2x – 3 = 0


x =







= 0


Therefore,


(2x – 3) is a factor of (2x4 + x3 – 8x2 – x + 6)



Question 7.

is a factor of


Answer:

From the factor theorem, we have


(x – a) is the factor of f(x) if f(a) = 0


Here, we have



= 14 – 8 – 6


= 14 – 14


= 0


Therefore,


(x - ) is a factor of (7x2 - 4√2x – 6)



Question 8.

is a factor of


Answer:

From the factor theorem, we have


(x – a) is the factor of f(x) if f(a) = 0


Here, we have





= 0


Therefore,


(x + √2) is the factor of (2√2x2 + 5x + √2)



Question 9.

Find the value of k for which (x-1) is a factor of


Answer:

Let, f(x) = 2x3 + 9x2 + x + k


Now, we have


x – 1 = 0


x = 1


Hence,


f(1) = 2 × 13 + 9 × 12 + 1 + k


= 2 + 9 + 1 + k


= 12 + k


As per the question,


(x – 1) is the factor of f(x)


Now, by using factor theorem we get


(x – a) will be a factor of f(x) only if f(a) = 0 and hence f(1) = 0


So,


f(1) = 0


0 = 12 + k


k = -12



Question 10.

Find the value of a for which (x-4) is a factor of


Answer:

Let, f(x) = 2x3 – 3x2 – 18x + a


Now, we have


x - 4 = 0


x = 4


Hence,


f(4) = 2(4)3 – 3(4)2 – 18 × 4 + a


= 128 – 48 – 72 + a


= 128 – 120 + 8


= 8 + a


As per question,


(x - 4) is the factor of f(x)


Now, by using factor theorem we get


(x – a) will be the factor of f(x) if f(a) = 0 and hence f(4) = 0


So,


f(4) = 8 + a = 0


a = -8



Question 11.

Find the value of a for which the polynomial is divisible by (x+3).


Answer:

Let, f(x) = x4 – x3 – 11x2 - x + a


Now, we have


x + 3 = 0


x = -3


Hence,


f(-3) = (-3)4 – (-3)3 – 11(-3)2 – (-3) + a


= 81 + 27 – 11 × 9 + 3 + a


= 81 + 27 – 99 + 3 + a


= 111 – 99 + a


= 12 + a


As per question,


(x + 3) is the factor of f(x)


Now, by using factor theorem we get


(x – a) will be the factor of f(x) if f(a) = 0 and hence f(-3) = 0


So,


f(-3) = 12 + a = 0


a = -12



Question 12.

For what value of a is the polynomial exactly divisible by (2x-1)?


Answer:

Let, f(x) = 2x3 + ax2 + 11x + a + 3


Now, we have


2x – 1 = 0


x = 1/2


As per the question,


f(x) is exactly divisible by 2x – 1 which means that 2x – 1 is a factor of f(x)


Hence,


Using factor theorem,


(x – a) will be a factor of f(x) if f(a) = 0 and hence,


f() 0


Hence,







= 5a = -35


a = -7


Thus, the value of a is -7



Question 13.

Find the values of a and b so that the polynomial is exactly divisible by (x-1) as well as (x-2).


Answer:

Let f(x) = x3 – 10x2 + ax + b


Now,


By using factor theorem,


(x – 1) and (x - 2) will be the factors of f(x) if f(1) = 0 and f(2) = 0


Hence,


f(1) = 13 – 10 (1)2 + a × 1 + b
0 = 1 – 10 + a + b


a + b = 9 (i)


And,


f(2) = 23 – 10 × 22 + a × 1 + b


0 = 8 – 40 + 2a + b


2a + b = 32 (ii)


Now, subtracting (i) from (ii)


a = 23


Using the value of a in (i), we get


23 + b = 9


b = 9 – 23


b = -14


Hence,


a = 23 and b = -14



Question 14.

Find the values of a and b so that the polynomial is

exactly divisible by (x+2) as well as (x+3).


Answer:

Let f(x) = x4 + ax3 – 7x2 - 8x + b


Now,


(x + 2) = 0


x = -2


And,


(x + 3) = 0


x = -3


Now,


By using factor theorem,


(x + 2) and (x + 3) will be the factors of f(x) if f(-2) = 0 and f(-3) = 0


Hence,


f(-2) = (-2)4 + a(-2)3- 7 (-2)2 -8 (-2) + b
0 = 16 – 8a - 28 + 16 + b


8a - b = 4 (i)


And,


f(-3) = (-3)4 + a (-3)3 – 10 (-3)2 – 8 (-3) + b


0 = 81 – 27a – 63 + 24 + b


27a – b = 42 (ii)


Now, subtracting (i) from (ii)


19a = 38


a = 2


Using the value of a in (i), we get


8 (2) – b = 4


16 – b = 4


b = 12


Therefore,


a = 2 and b = 12



Question 15.

Without actual division, show that is exactly divisible by .


Answer:

Let f(x) = x3 – 3x2 – 13x + 15


Now, we have


x2 + 2x – 3 = 0


x2 + 3x – x – 3 = 0


(x + 3)(x – 1)


Hence, f(x) will be exactly divisible by x2 + 2x – 3 = (x + 3)(x – 1)


Now,


Using factor theorem,


If (x + 3) and (x – 1) are both the factors of f(x), then f(-3) = 0 and f(1) = 0


Now,


f(-3) = (-3)3 – 3(-3)2 – 13(-3) + 15


= - 27 – 27 + 39 + 15


= - 54 + 54


= 0


And,


f(1) = (1)3 – 3(1)2 – 13(1) + 15


= 1 – 3 - 13 + 15


= 16 - 16


= 0


Now,


Since, f(-3) = 0 and f(1) = 0


Therefore, x2 + 2x -3 divides f(x) completely.



Question 16.

If has (x-2) as a factor and leaves a remainder 3 when divided by (x-3), find the values of a and b.


Answer:

Let f(x) = (x3 + ax2 + bx + 6)


By using remainder theorem,


If we divide f(x) by (x – 3) then it will leave a remainder as f(3)


So,


f(3) = 32 + a × 32 + b × 3 + 6 = 3


27 + 9a + 3b + 6 = 3


9a + 3b + 33 = 3


9a + 3b = 3 – 33


9a + 3b = -30


3a + b = -10 (i)


It is also given that,


(x – 2) is a factor of f(x)


Therefore,


By using factor theorem, we get


(x – a) is the factor of f(x) if f(a) = 0and also f(2) = 0


Now,


f(2) = 23 + a × 22 + b × 2 + 6 = 0


8 + 4a + 2b + 6 = 0


4a + 2b = -14


2a + b = -7 (ii)


Now by subtracting (ii) from (i), we get


a = -3


Putting the value of a in (i), we get


3(-3) + b = -10


-9 + b = -10


b = -10 + 9


b = -1


Therefore,


b = -1 and a = -3




Exercise 2e
Question 1.

Factorize:

9x2 + 12xy


Answer:

We have,



At first, we’ll take common from the expression



Hence,


The given expression can be factorized as:


3x(3x + 4y)



Question 2.

Factorize:

18x2y – 24 xyz


Answer:

We have,



At first we’ll take common from the expression



Hence,


The given expression can be factorized as:




Question 3.

Factorize:

27a3b3 – 45a4b2


Answer:

We have,



At first we’ll take common from the expression



Hence,


The given expression can be factorized as:




Question 4.

Factorize:

2a(x + y) -3b(x + y)


Answer:

We have,



At first, we’ll take common from the expression



Hence,


The given expression can be factorized as:




Question 5.

Factorize:

2x(p2 + q2) +4y (p2 + q2)


Answer:

We have,



At first, we’ll take common from the expression


=2[x (p2 + q2) + 2y (p2 + q2)]


=


Hence,


The given expression can be factorized as:




Question 6.

Factorize:

x(a - 5) + y (5 - a)


Answer:

We have,



At first we’ll take common from the expression


= (a – 5) (x – y)


Hence,


The given expression can be factorized as:




Question 7.

Factorize:

4(a + b) – 6 (a + b)2


Answer:

We have,



At first, we’ll take (a+b) common from the expression.


= (a + b) [4 – 6 (a + b)]

Take 2 common out of [4 - 6(a+b)]

= 2(a + b) (2 – 3a – 3b)


Hence,


The given expression can be factorized as:



Question 8.

Factorize:

8(3a – 2b)2 – 10 (3a – 2b)


Answer:

We have,



At first we’ll take common from the expression


= (3a – 2b) [8 (3a – 2b) – 10]


= (3a – 2b) 2[4 (3a – 2b) – 5]


= 2 (3a - 2b) (12a – 8b – 5)


Hence,


The given expression can be factorized as:




Question 9.

Factorize:

x(x + y)3 – 3x2y (x + y)


Answer:

We have,



At first we’ll take common from the expression


= x (x + y) [(x + y)2 – 3xy]


= x (x + y) (x2 + y2 + 2xy – 3xy)


= x (x + y) (x2 + y2 – xy)


Hence,


The given expression can be factorized as:




Question 10.

Factorize:

x3 + 2x2 + 5x + 10


Answer:

We have,



At first we’ll take common from the expression


= x2 (x + 2) + 5 (x + 2)


= (x2 + 5) (x + 2)


Hence,


The given expression can be factorized as:




Question 11.

Factorize:

x2 + xy – 2xz – 2yz


Answer:

We have,



At first we’ll take common from the expression


= x (x + y) – 2z (x + y)


= (x + y) (x – 2z)


Hence,


The given expression can be factorized as:




Question 12.

Factorize:

a3b – a2b + 5ab – 5b


Answer:

We have,



At first we’ll take common from the expression


= a2b (a – 1) + 5b (a – 1)


= (a – 1) (a2b + 5b)


= (a – 1) b (a2 + 5)


= b (a – 1) (a2 + 5)


Hence,


The given expression can be factorized as:




Question 13.

Factorize:

8 – 4a – 2a3 + a4


Answer:

We have,



At first we’ll take common from the expression


= 4 (2 – a) - a3 (2 – a)


= (2 – a) (4 – a3)


Hence,


The given expression can be factorized as:




Question 14.

Factorize:

x3 – 2x2y + 3xy2 – 6y3


Answer:

We Have,



At first we’ll take common from the expression


= x2 (x – 2y) + 3y2 (x – 2y)


= (x – 2y) (x2 + 3y2)


Hence,


The given expression can be factorized as:




Question 15.

Factorize:

px – 5q + pq – 5x


Answer:

We have,



At first we’ll take common from the expression


= p (x + q) – 5 (q + x)


= (x + q) (p – 5)


Hence,


The given expression can be factorized as:




Question 16.

Factorize:

x2 + y – xy - x


Answer:

We have,



At first we’ll take common from the expression


= x (x – y) – 1 (x – y)


= (x – y) (x – 1)


Hence,


The given expression can be factorized as:




Question 17.

Factorize:

(3a - 1)2 – 6a + 2


Answer:

We have,



At first, we’ll take 2 common from - 6a + 2 in the expression.


= (3a – 1)2 – 2 (3a – 1)

Now take (3a-1) common from above to get,

= (3a – 1) [(3a – 1) – 2]


= (3a – 1) (3a – 3)


= 3(3a – 1) (a – 1)


Hence,


The given expression can be factorized as:



Question 18.

Factorize:

(2x - 3)2 – 8x + 12


Answer:

We have,



At first we’ll take common from the expression


= (2x – 3)2 – 4 (2x – 3)


= (2x – 3) (2x – 3 – 4)


= (2x – 3) (2x – 7)


Hence,


The given expression can be factorized as:




Question 19.

Factorize:

a2 + a – 3a2 - 3


Answer:

We have,



At first we’ll take common from the expression


= a (a2 + 1) – 3 (a2 + 1)


= (a – 3) (a2 + 1)


Hence,


The given expression can be factorized as:




Question 20.

Factorize:

3ax – 6ay – 8by + 4bx


Answer:

We have,



At first we’ll take common from the expression


= 3a (x – 2y) + 4b (x – 2y)


= (x – 2y) (3a + 4b)


Hence,


The given expression can be factorized as:




Question 21.

Factorize:

abx2 + a2x + b2x + ab


Answer:

We have,



At first we’ll take common from the expression


= ax (bx + a) + b (bx + a)


= (bx + a) (ax + b)


Hence,


The given expression can be factorized as:




Question 22.

Factorize:

x3 – x2 + ax + x – a – 1


Answer:

We have,



At first we’ll take common from the expression


= x3 – x2 + ax – a + x – 1


= x2 (x – 1) + a (x – 1) + 1 (x – 1)


= (x – 1) (x2 + a + 1)


Hence,


The given expression can be factorized as:




Question 23.

Factorize:

2x + 4y – 8xy – 1


Answer:

We have,



At first we’ll take common from the expression


= 2x – 1 – 8xy + 4y


= (2x – 1) – 4y (2x – 1)


= (2x – 1) (1 – 4y)


Hence,


The given expression can be factorized as:




Question 24.

Factorize:

ab(x2 + y2) – xy(a2 + b2)


Answer:

We have,



At first we’ll take common from the expression


= abx2 + aby2 – a2xy – b2xy


= abx2 – a2xy + aby2 – b2xy


= ax (bx – ay) + by (ay – bx)


= (bx – ay) (ax – by)


Hence,


The given expression can be factorized as:




Question 25.

Factorize:

a2 + ab(b + 1) + b3


Answer:

We have,



At first we’ll take common from the expression


= a2 + ab2 + ab + b3


= a2 + ab + ab2 + b3


= a (a + b) + b2 (a + b)


= (a + b) (a + b2)


Hence,


The given expression can be factorized as:




Question 26.

Factorize:

a3 + ab(1 – 2a) – 2b2


Answer:

We have,



At first we’ll take common from the expression


= a3 + ab – 2a2b – 2b2


= a (a2 + b) – 2b (a2 + b)


= (a2 + b) (a – 2b)


Hence,


The given expression can be factorized as:




Question 27.

Factorize:

2a2 + bc – 2ab – ac


Answer:

We have,



At first we’ll take common from the expression


= 2a2 – 2ab – ac + bc


= 2a (a – b) – c (a – b)


= (a – b) (2a – c)


Hence,


The given expression can be factorized as:




Question 28.

Factorize:

(ax + by)2 + (bx - ay)2


Answer:

We have,



At first we’ll take common from the expression


= a2x2 + b2y2 + 2abxy + b2x2 + a2y2 – 2abxy


= a2x2 + b2y2 + b2x2 + a2y2


= a2x2 + b2x2 + b2y2 + a2y2


= x2 (a2 + b2) + y2 (a2 + b2)


= (a2 + b2) (x2 + y2)


Hence,


The given expression can be factorized as:




Question 29.

Factorize:

a(a + b – c) – bc


Answer:

We have,



At first we’ll take common from the expression


= a2 + ab – ac – bc


= a (a + b) – c (a + b)


= (a – c) (a + b)


Hence,


The given expression can be factorized as:




Question 30.

Factorize:

a(a – 2b – c) + 2bc


Answer:

We have,



At first we’ll take common from the expression


= a2 – 2ab – ac + 2bc


= a (a – 2b) – c (a – 2b)


= (a – 2b) (a – c)


Hence,


The given expression can be factorized as:




Question 31.

Factorize:

a2x2 + (ax2 + 1)x + a


Answer:

We have,



At first, we’ll take common from the expression


= a2x2 + ax3 + x + a


= ax2 (a + x) + 1 (x + a)


= (ax2 + 1) (a + x)


Hence,


The given expression can be factorized as:




Question 32.

Factorize:

ab(x2 + 1) + x(a2 + b2)


Answer:

We have,



At first, we’ll take common from the expression


= abx2 + ab + a2x + b2x


= abx2 + a2x + ab + b2x


= ax (bx + a) + b (bx + a)


= (bx + a) (ax + b)


Hence,


The given expression can be factorized as:




Question 33.

Factorize:

x2 – (a + b)x + ab


Answer:

We have,



At first we’ll take common from the expression


= x2 - ax – bx + ab


= x (x – a) – b (x – a)


= (x – a) (x – b)


Hence,


The given expression can be factorized as:




Question 34.

Factorize:



Answer:

We have,



At first, we’ll take common from the expression


= (x - 1/x)2 – 3 (x – 1/x)


=


Hence,


The given expression can be factorized as:





Exercise 2f
Question 1.

Factorize:

25x2 – 64y2


Answer:

We have,



We can also write the expression as:


(5x)2 – (8y)2


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 2.

Factorize:

100 – 9x2


Answer:

We have,



We can also write the expression as:


(10)2 – (3x)2


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 3.

Factorize:

5x2 – 7y2


Answer:

We have,



We can also write the expression as:


(x)2 – (y)2


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 4.

Factorize:

(3x + 5y)2 – 4z2


Answer:

We have,



We can also write the expression as:


(3x + 5y)2 – (2z)2


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 5.

Factorize:

150 – 6x2


Answer:

We have,



= 6(25 – x2)


We can also write the expression as:


6[(5 )2 – (x)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)


6(5 - x) (5 + x)


Hence,


The given expression can be factorized as: 6(5 - x)(5 + x)



Question 6.

Factorize:

20x2 – 45


Answer:

We have,



= 5(x2 – 9)


We can also write the expression as:


= 5(x – 9)(x + 9)


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 7.

Factorize:

3x3 - 48


Answer:

We have,


3x3 - 48


= 3x(x2 - 16)


We can also write the expression as:


3x[(x)2 – (4)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 8.

Factorize:

2 – 50x2


Answer:

We have,



= 2(1 – 25x2)


We can also write the expression as:


= 2[(1)2 – (25x)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 9.

Factorize:

27a2 – 48b2


Answer:

We have,



= 3(9a2 – 16b2)


We can also write the expression as:


= 3[(3a)2 – (4b)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 10.

Factorize:

x – 64x3


Answer:

We have,



= x(1 – 64x2)


We can also write the expression as:


= x[(1)2 – (8x)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 11.

Factorize:

8ab2 – 18a3


Answer:

We have,



= 2a(4b2 – 9a2)


We can also write the expression as:


= 2a[(2b)2 – (3a)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 12.

Factorize:

3a3b – 243ab3


Answer:

We have,



= 3ab(a2 – 81b2)


We can also write the expression as:


= 3ab[(a)2 – (9b)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 13.

Factorize:

(a + b)3 – a – b


Answer:

We have,



= (a + b)3 – (a + b)


= (a + b) [(a + b)2 – 1]


We can also write the expression as:


= (a + b)[(a + b)2 – (1)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 14.

Factorize:

108a2 –3(b – c)2


Answer:

We have,



= 3[36a2 – (b – c)2]


We can also write the expression as:


= 3[(6a)2 – (b – c)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 15.

Factorize:

x3 – 5x2 – x + 5


Answer:

We have,



= x2(x – 5) – 1(x – 5)


= (x - 5)[x2 – (1)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 16.

Factorize:

a2 + 2ab + b2 – 9c2


Answer:

We have,



= (a + b)2 – 9c2


We can also write the expression as:


= [(a + b)2 – (3c)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 17.

Factorize:

9 – a2 + 2ab – b2


Answer:

We have,



= [9 – (a2 – 2ab + b)2]


We can also write the expression as:


= [(3)2 – (a – b)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 18.

Factorize:

a2 – b2 –4ac + 4c2


Answer:

We have,



= a2 – 2(a)(2c) + c2 – b2


= (a – c)2 – (b)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 19.

Factorize:

9a2 + 3a – 8b – 64b4


Answer:

We have,



= 9 a2 – 64b2 + 3a – 8b


We can also write this as:


= (3a)2 –(8b)2 + ( 3a – 8b)


Now,


Using identity: a2 - b2 = (a – b)(a + b)




Question 20.

Factorize:

x2 – y2 + 6y – 9


Answer:

We have,



= [x2 – (y2 – 2(y)(3) + 32]


We can also write the expression as:


= [(x)2 – (y – 3)2]


Now,


Using identity: a2 – b2 = (a – b)(a + b)



Hence,


The given expression can be factorized as:



Question 21.

Factorize:

4x2 – 9y2 – 2x – 3y


Answer:

We have,



We can also write this as:


= (4x)2 –(9y)2 – ( 2x + 3y)


Now,


Using identity: a2 - b2 = (a – b)(a + b)




Question 22.

Factorize:

x4 – 1


Answer:

We have:



We can also write this as:


=(x2)2 - 12


Using identity: a2 - b2 = (a – b)(a + b)


=(x2 + 1)(x2 – 1)


Again,


Using identity: a2 - b2 = (a – b)(a + b)


=(x2 + 1)(x + 1)(x – 1)



Question 23.

Factorize:

a – b – a2 + b2


Answer:

We have:



= (a – b) – (a2 - b2)


= (a – b) – (a – b)(a + b)


Hence,


The factorization of the given expression is,




Question 24.

Factorize:

x4 – 625


Answer:

We have:



We can also write this as:


=(x2)2 – (25)2


Using identity: a2 - b2 = (a – b)(a + b)


=(x2 + 25)(x2 – 25)


Again,


Using identity: a2 - b2 = (a – b)(a + b)





Exercise 2g
Question 1.

Factorize:

x2 + 11x + 30


Answer:

We have,



Now by using middle-term splitting, we get


= x2 + 6x + 5x + 30


= x (x + 6) + 5 (x + 6)


= (x + 6) (x + 5)


Hence,


The given expression can be factorized as:




Question 2.

Factorize:

x2 + 18x + 32


Answer:

We have,



Now by using middle-term splitting, we get


= x2 + 16x + 2x + 32


= x (x + 16) + 2 (x + 16)


= (x + 16) (x + 2)


Hence,


The given expression can be factorized as:




Question 3.

Factorize:

x2 + 7x – 18


Answer:

We have,



Now by using middle-term splitting, we get


= x2 + 9x - 2x - 18


= x (x + 9) - 2 (x + 9)


= (x + 9) (x - 2)


Hence,


The given expression can be factorized as:




Question 4.

Factorize:

x2 + 5x – 6


Answer:

We have,



Now by using middle-term splitting, we get


= x2 + 6x - x - 6


= x (x + 6) - 1 (x + 6)


= (x + 6) (x - 1)


Hence,


The given expression can be factorized as:




Question 5.

Factorize:

y2 – 4y + 3


Answer:

We have,



Now by using middle-term splitting, we get


= y2 – 3y - y + 3


= y (y - 3) - 1 (y - 3)


= (y - 3) (y - 1)


Hence,


The given expression can be factorized as:




Question 6.

Factorize:

x2 – 21x + 108


Answer:

We have,



Now by using middle-term splitting, we get


= x2 - 12x - 9x + 108


= x (x -12) - 9 (x -12)


= (x -12) (x - 9)


Hence,


The given expression can be factorized as:




Question 7.

Factorize:

x2 – 11x – 80


Answer:

We have,



Now by using middle-term splitting, we get


= x2 - 16x + 5x - 80


= x (x - 16) + 5 (x - 16)


= (x - 16) (x + 5)


Hence,


The given expression can be factorized as:




Question 8.

Factorize:

x2 – x – 156


Answer:

We have,



Now by using middle-term splitting, we get


= x2 - 13x + 12x - 156


= x (x - 13) + 12 (x - 13)


= (x - 13) (x + 12)


Hence,


The given expression can be factorized as:




Question 9.

Factorize:

z2 – 32z – 105


Answer:

We have,



Now by using middle-term splitting, we get


= z2 – 35z + 3z - 105


= z (z - 35) + 3 (z - 35)


= (z - 35) (z + 3)


Hence,


The given expression can be factorized as:




Question 10.

Factorize:

40 + 3x – x2


Answer:

We have,



Now by using middle-term splitting, we get


= 40 + 8x – 5x – x2


= 8 (5 + x) – x (5 + x)


= (5 + x) (8 – x)


Hence,


The given expression can be factorized as:




Question 11.

Factorize:

6x – x – x2


Answer:

We have,



Now by using middle-term splitting, we get


= 6 + 2x – 3x – x2


= 2 (3 + x) – x (3 + x)


= (3 + x) (2 – x)


Hence,


The given expression can be factorized as:




Question 12.

Factorize:

7x2 + 49x + 84


Answer:

We have,



Now by using middle-term splitting, we get


= 7 (x2 +7x + 12)


= 7 [x2 + 4x + 3x + 12]


= 7 [x (x + 4) + 3 (x + 4)]


= 7 (x + 4) (x + 3)


Hence,


The given expression can be factorized as:




Question 13.

Factorize:

m2 + 17mn – 84


Answer:

We have,



Now by using middle-term splitting, we get


= m2 + 21mn– 4mn – 84n2


= m (m + 21n) – 4n (m + 21n)


= (m + 21n) (m – 4n)


Hence,


The given expression can be factorized as:




Question 14.

Factorize:

5x2 + 16x + 3


Answer:

We have,



Now by using middle-term splitting, we get


= 5x2 + 15x + x + 3


= 5x (x + 3) + 1 (x + 3)


= (5x + 1) (x + 3)


Hence,


The given expression can be factorized as:




Question 15.

Factorize:

6x2 + 17x + 12


Answer:

We have,



Now by using middle-term splitting, we get


= 6x2 + 9x + 8x + 12


= 3x (2x + 3) + 4 (2x + 3)


= (2x + 3) (3x + 4)


Hence,


The given expression can be factorized as:




Question 16.

Factorize:

9x2 + 18x + 8


Answer:

We have,



Now by using middle-term splitting, we get


= 9x2 + 12x + 6x + 8


= 3x (3x + 4) + 2 (3x + 4)


= (3x + 4) (3x + 2)


Hence,


The given expression can be factorized as:




Question 17.

Factorize:

14x2 + 9x + 1


Answer:

We have,



Now by using middle-term splitting, we get


= 14x2 + 7x + 2x + 1


= 7x (2x + 1) + 1 (2x + 1)


= (7x + 1) (2x + 1)


Hence,


The given expression can be factorized as:




Question 18.

Factorize:

2x2 + 3x – 90


Answer:

We have,



Now by using middle-term splitting, we get


= 2x2 - 12x + 15x - 90


= 2x (x - 6) + 15 (x - 6)


= (x - 6) (2x + 15)


Hence,


The given expression can be factorized as:




Question 19.

Factorize:

2x2 + 11x – 21


Answer:

We have,



Now by using middle-term splitting, we get


= 2x2 + 14x - 3x - 21


= 2x (x + 7) - 3 (x + 7)


= (x + 7) (2x - 3)


Hence,


The given expression can be factorized as:




Question 20.

Factorize:

3x2 – 14x + 8


Answer:

We have,



Now by using middle-term splitting, we get


= 3x2 - 12x - 2x + 8


= 3x (x - 4) - 2 (x - 4)


= (x - 4) (3x - 2)


Hence,


The given expression can be factorized as:




Question 21.

Factorize:

18x2 + 3x – 10


Answer:

We have,



Now by using middle-term splitting, we get


= 18x2 - 12x + 15x - 10


= 6x (3x - 2) + 5 (3x - 2)


= (6x + 5) (3x - 2)


Hence,


The given expression can be factorized as:




Question 22.

Factorize:

15x2 + 2x – 8


Answer:

We have,



Now by using middle-term splitting, we get


= 15x2 - 10x + 12x - 8


= 5x (3x - 2) + 4 (3x - 2)


= (5x + 4) (3x - 2)


Hence,


The given expression can be factorized as:




Question 23.

Factorize:

6x2 + 11x – 10


Answer:

We have,



Now by using middle-term splitting, we get


= 6x2 + 15x - 4x - 10


= 3x (2x + 5) - 2 (2x + 5)


= (2x + 5) (3x - 2)


Hence,


The given expression can be factorized as:




Question 24.

Factorize:

30x2 + 7x – 15


Answer:

We have,



Now by using middle-term splitting, we get


= 30x2 - 18x + 25x - 15


= 6x (5x - 3) + 5 (5x - 3)


= (5x - 3) (6x + 5)


Hence,


The given expression can be factorized as:




Question 25.

Factorize:

24x2 – 41x + 12


Answer:

We have,



Now by using middle-term splitting, we get


= 24x2 - 32x - 9x + 12


= 8x (3x - 4) - 3 (3x - 4)


= (3x - 4) (8x - 3)


Hence,


The given expression can be factorized as:




Question 26.

Factorize:

2x2 – 7x – 15


Answer:

We have,



Now by using middle-term splitting, we get


= 2x2 - 10x + 3x - 15


= 2x (x - 5) + 3 (x - 5)


= (x - 5) (2x + 3)


Hence,


The given expression can be factorized as:




Question 27.

Factorize:

6x2 – 5x – 21


Answer:

We have,



Now by using middle-term splitting, we get


= 6x2 + 9x - 14x - 21


= 3x (2x + 3) - 7 (2x + 5)


= (3x - 7) (2x + 3)


Hence,


The given expression can be factorized as:




Question 28.

Factorize:

10x2 – 9x – 7


Answer:

We have,



Now by using middle-term splitting, we get


= 10x2 + 5x - 14x - 7


= 5x (2x + 1) - 7 (2x + 1)


= (2x + 1) (5x - 7)


Hence,


The given expression can be factorized as:




Question 29.

Factorize:

5x2 – 16x – 21


Answer:

We have,



Now by using middle-term splitting, we get


= 5x2 + 5x - 21x - 21


= 5x (x + 1) - 21 (x + 1)


= (x + 1) (5x - 21)


Hence,


The given expression can be factorized as:




Question 30.

Factorize:

2x2 – x – 21


Answer:

We have,



Now by using middle-term splitting, we get


= 2x2 + 6x - 7x - 21


= 2x (x + 3) - 7 (x + 3)


= (x + 3) (2x - 7)


Hence,


The given expression can be factorized as:



Question 31.

Factorize:

15x2 – x – 28


Answer:

We have,



Now by using middle-term splitting, we get


= 15x2 + 20x - 21x - 28


= 5x (3x + 4) - 7 (3x + 4)


= (3x + 4) (5x - 7)


Hence,


The given expression can be factorized as:




Question 32.

Factorize:

8a2 – 27ab + 9b2


Answer:

We have,



Now by using middle-term splitting, we get


= 8a2 – 24ab – 3ab + 9b2


= 8a (a – 3b) – 3b (a – 3b)


= (a – 3b) (8a – 3b)


Hence,


The given expression can be factorized as:




Question 33.

Factorize:

5x2 + 33xy – 14y2


Answer:

We have,



Now by using middle-term splitting, we get


= 5x2 + 35xy – 2xy – 14y2


= 5x (x + 7y) – 2y (x + 7y)


= (x + 7y) (5x – 2y)


Hence,


The given expression can be factorized as:




Question 34.

Factorize:

3x3 – x2 – 10x


Answer:

We have,



Now by using middle-term splitting, we get


= x (3x2 – x – 10)


= x [3x2 – 6x + 5x – 10]


= x [3x (x – 2) + 5 (x – 2)]


= x (x – 2) (3x + 5)


Hence,


The given expression can be factorized as:




Question 35.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 1/3 x2 – 3x + x – 9


= x (x/3 – 3) + (x – 9)


= x/3 (x – 9) + 1 (x – 9)


= (x – 9) (x/3 + 1)


= (x – 9) × (x – 3)/3


= 1/3 (x – 9) (x + 3)


Hence,


The given expression can be factorized as:




Question 36.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 1/16 (16x2 – 32x + 7)


= 1/16 (16x2 – 4x – 28x + 7)


= 1/16 [4x (4x – 1) – 7 (4x – 1)]


= 1/16 (4x – 1) (4x – 7)


Hence,


The given expression can be factorized as:




Question 37.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


=x2 + x + 2x +


= x (√2 x+1) + √2 (√2 x+1)


=


Hence,


The given expression can be factorized as:




Question 38.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= √5 × x × x + 5x – 3x - 3√5


= √5 x (x + √5) – 3 ( x + √5)


= (√5 x – 3) (x + √5)


Hence,


The given expression can be factorized as:




Question 39.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 2 × x × x + 2√3x + √3x + 3


= 2x (x+ √3) + √3 (x + √3)


= (x + √3) (2x + √3)


Hence,


The given expression can be factorized as:




Question 40.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 2√3 * x * x + 6x - 5x - 5√3


= 2 √3 x (x + √3) - 5 (x+ √3)


= (x + √3)(2√3x - 5)


Hence,


The given expression can be factorized as:




Question 41.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 5√5 * x * x + 15x + 5x + 3√5


= 5x (√5x + 3) + √5 (√5x + 3)


= (√5x + 3)(5x + √5)


Hence,


The given expression can be factorized as:




Question 42.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 7√2 * x * x - 14x + 4x - 4√2


= 7√2x (x - √2) + 4 (x- √2)


= (x - √2) (7√2 x+4)


Hence,


The given expression can be factorized as:




Question 43.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 6√3 * x * x - 45x - 2x + 5√3


= 3√3 x (2x - 5√3) - 1 (2x- 5√3)


= (2x - 5√3)(3√3 x - 1)


Hence,


The given expression can be factorized as:




Question 44.

Factorize:



Answer:

We have,



Now by using middle-term splitting, we get


= 7*x*x + √2 × √7x + √2 × √7 x + 2


= √7x (√7x + √2) + √2 (√7x + √2)


= (√7x + √2)(√7x + √2)


= (√7x + √2)2


Hence,


The given expression can be factorized as:




Question 45.

Factorize:

2(x + y)2 –9(x + y) – 5


Answer:

We have,



Let x + y = z


Then,


2 (x + y)2 – 9 (x + y) - 5


Now by using middle-term splitting, we get


= 2z2 - 9z - 5


= 2z2 – 10z + z – 5


= 2z (z – 5) + 1 (z – 5)


= (z – 5) (2z + 1)


Now,


Replacing z by (x + y), we get


2 (x + y)2 - 9 (x + y) – 5


= [(x + y) – 5] [2 (x + y) + 1]


= (x + y – 5) (2x + 2y + 1)


Hence,


The given expression can be factorized as:




Question 46.

Factorize:

9(2a – b)2 – 4(2a – b) – 13


Answer:

We have,



Let 2a – b = c


Then,


9 (2a - b)2 – 4 (2a - b) - 13


Now by using middle-term splitting, we get


= 9c2 – 4c - 13


= 9c2 – 13c + 9c – 13


= c (9c – 13) + 1 (9c – 13)


= (c + 1) (9c - 13)


Now,


Replacing c by (2a - b) - 13, we get


9 (2a – b)2 – 4 (2a – b) - 13


= (2a – b + 1) [9 (2a – b) – 13]


= (2a – b + 1) (18a – 9b – 13)


Hence,


The given expression can be factorized as:




Question 47.

Factorize:

7(x – 2y)2 – 25(x – 2y) + 12


Answer:

We have,



Let x - 2y = z


Then,


7 (x - 2y)2 – 25 (x - 2y) + 12


Now by using middle-term splitting, we get


= 7z2 - 25z + 12


= 7z2 – 21z - 4z + 12


= 7z (z – 3) - 4 (z – 3)


= (z – 3) (7z - 4)


Now,


Replacing z by (x - 2y), we get


7 (x - 2y)2 - 25 (x - 2y) + 12


= (x - 2y – 3) [7 (x - 2y) - 4]


= (x - 2y – 3) (7x - 14y - 4)


Hence,


The given expression can be factorized as:




Question 48.

Factorize:

4x4 + 7x2 – 2


Answer:

We have,



Now by using middle-term splitting, we get


= 4y2 + 7y – 2


= 4y2 + 8y – y – 2


= 4y (y + 2) – (y + 2)


= (y + 2) (4y – 1)


Now,


Replacing y by x2, we get


4x4 + 7x2 – 2


= (x2 + 2) (4x2 – 1) [Therefore, a2 – b2 = (a – b) (a + b)]


= (x2 + 2) (2x + 1) (2x – 1)


Hence,


The given expression can be factorized as:





Exercise 2h
Question 1.

Expand:

(i) (a + 2b + 5c)2

(ii) (2a – b + c)2

(iii) (a – 2b – 3c)2


Answer:

(i) We know that,


(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca


Using this formula, we get


= (a)2 + (2b)2 + (5c)2 + 2(a) (2b) + 2 (2b) (5c) + 2 (5c) (a)


= a2 + 4b2 + 25c2 + 4ab + 20bc + 10ac


(ii) We know that,


(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca


Using this formula, we get


= (2a)2 + (-b)2 + (c)2 + 2(2a) (-b) + 2 (-b) (c) + 2 (c) (2a)


= 4a2 + b2 + c2 - 4ab - 2bc + 4ac


(iii) We know that,


(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca


Using this formula, we get


= (a)2 + (-2b)2 + (-3c)2 + 2(a) (-2b) + 2 (-2b) (-3c) + 2 (-3c) (a)


= a2 + 4b2 + 9c2 - 4ab + 12bc - 6ac



Question 2.

Expand

(i) (2a – 5b – 7c)2

(ii) (–3a + 4b – 5c)2

(iii)


Answer:

(i) We know that,


(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca


Using this formula, we get


= (2a)2 + (-5b)2 + (-7c)2 + 2(2a) (-5b) + 2 (-5b) (-7c) + 2 (-7c) (2a)


= 4a2 + 25b2 + 49c2 - 20ab + 70bc - 28ac


(ii) We know that,


(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca


Using this formula, we get


= (-3a)2 + (4b)2 + (-5c)2 + 2(-3a) (4b) + 2 (4b) (-5c) + 2 (-5c) (-3a)


= 9a2 + 16b2 + 25c2 - 24ab - 40bc + 30ac


(iii) We know that,


(a + b + c)2 = a2 + b2 + c2 + 2ab + 2bc + 2ca


Using this formula, we get


= (1/2a)2 + (-1/4b)2 + (2)2 + 2(1/2a) (-1/4b) + 2 (-1/4b) (2) + 2 (2) (1/2a)


=



Question 3.

Factorize:

4x2 + 9y2 + 16z2 + 12xy – 24yz – 16xz


Answer:

We know that,


(x + y + z)2 = x2 + y2 + z2 + 2xy + 2yz + 2za


Using this formula, we get


= (2x)2 + (3y)2 + (-4z)2 + 2(2x) (3y) + 2 (3y) (-4z) + 2 (-4z) (2x)


= (2x + 3y – 4z)2



Question 4.

Factorize:

9x2 + 16y2 + 4z2 –24xy + 16yz – 12xz


Answer:

We know that,


(x + y + z)2 = x2 + y2 + z2 + 2xy + 2yz + 2za


Using this formula, we get


= (-3x)2 + (4y)2 + (2z)2 + 2(-3x) (4y) + 2 (4y) (2z) + 2 (2z) (-3x)


= (-3x + 4y + 2z)2



Question 5.

Factorize:

25x2 + 4y2 + 9z2 – 20xy – 12yz + 30xz


Answer:

We know that,


(x + y + z)2 = x2 + y2 + z2 + 2xy + 2yz + 2za


Using this formula, we get


= (5x)2 + (-2y)2 + (3z)2 + 2(5x) (-2y) + 2 (-2y) (3z) + 2 (3z) (5x)


= (5x – 2y + 3z)2



Question 6.

Evaluate:

(i) (99)2

(ii) (998)2


Answer:

(i) We know that,


(a – b)2 = a2 – 2ab + b2


Using this formula, we get


= (100 – 1)2


= (100)2 – 2(100) (1) + (1)2


= 10000 – 200 + 1


= 9801


(ii) We know that,


(a – b)2 = a2 – 2ab + b2


Using this formula, we get


= (1000 – 2)2


= (1000)2 – 2(1000) (2) + (2)2


= 1000000 – 4000 + 4


= 996004




Exercise 2i
Question 1.

Expand:

(i) (3x + 2)2

(ii) (3a – 2b)2

(iii)


Answer:

(i) We know that,


(a + b)3 = a3 + b3 + 3ab (a + b)


Using this formula, we get


= (3x)3 + (2)3 + 3 × 3x × 2 (3x + 2)


= 27x3 + 8 + 18x (3x + 2)


= 27x3 + 8 + 54x2 + 36x


(ii) We know that,


(a + b)3 = a3 + b3 + 3ab (a + b)


Using this formula, we get


= (3a)3 - (2b)3 - 3 × 3a × 2b (3a - 2)


= 27a3 – 8b3 – 18ab (3a – 2b)


= 27a3 – 8b3 – 54a2b + 36ab2


(iii) We know that,


(a + b)3 = a3 + b3 + 3ab (a + b)


Using this formula, we get


= (2/3x)3 + (1)3 + 3 × 2/3x × 1 (2/3x + 1)


= 8/27x3 + 1 + 2x (2/3x + 1)


=



Question 2.

Expand:

(i)

(ii)

(iii)


Answer:

(i) We know that,


(a – b)3 = a3 – b3 – 3ab (a – b)


Using this formula, we get


= (2x)3 – (2/x)3 – 3 × 2x × 2/x (2x – 2/x)


= 8x3 – 8/x3 – 12 (2x – 2/x)


=


(ii) We know that,


(a – b)3 = a3 – b3 – 3ab (a – b)


Using this formula, we get


= (3a)3 – (1/4b)3 + 3 × 3a × 1/4b (3a + 1/4b)


= 27a3 + 1/64b3 + 9a/4b (3a + 1/4b)


=


(iii) We know that,


(a – b)3 = a3 – b3 – 3ab (a – b)


Using this formula, we get


= (4/5x)3 – (2)3 - 3 × 4x/5 × 2 (3a + 1/4b)


= 64/125a3 – 8 - 24/5x (4/5x - 2)


=



Question 3.

Evaluate:

(i) (95)3

(ii) (999)3


Answer:

(i) We know that,


(a – b)3 = a3 – b3 – 3ab (a – b)


Using this formula, we get


= (100 – 5)3


= (100)3 – (5)3 – 3 × 100 × 5 (100 – 5)


= 1000000 – 125 – (1500 × 95)


= 857375


(ii) We know that,


(a – b)3 = a3 – b3 – 3ab (a – b)


Using this formula, we get


= (1000 – 1)3


= (1000)3 – (1)3 – 3 × 1000 × 1 (1000 – 1)


= 1000000000 – 1 – 3000 (1000 – 1)


= 1000000000 – 1 – 3000 × 1000 +3000 ×1


= 997002999