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Factorization

Class 8th Mathematics RD Sharma Solution
Exercise 7.1
  1. Find the greatest common factor (GCF/HCF) of the following polynomials 2x^2…
  2. 6x^3y 18x^2y^3 Find the greatest common factor (GCF/HCF) of the following…
  3. 7x , 21x^2 14xy^2 Find the greatest common factor (GCF/HCF) of the following…
  4. 42x^2yz 63x^3y^2z^3 Find the greatest common factor (GCF/HCF) of the following…
  5. 12ax^2 , 6a^2x^3 2a^3x^5 Find the greatest common factor (GCF/HCF) of the…
  6. 9x^2 , 15x^2y^3 , 6xy^2 21x^2y^5 Find the greatest common factor (GCF/HCF) of…
  7. 4a^2b^3 ,-21a^3b , 18a^4b^3 Find the greatest common factor (GCF/HCF) of the…
  8. 6x^2y^2 ,-9xy^3 , 3x^3y^2 Find the greatest common factor (GCF/HCF) of the…
  9. a^2b^3 , a^3b^2 Find the greatest common factor (GCF/HCF) of the following…
  10. 36a^2b^2c^4 , 54a^4c^2 , 90a^4b^2c^2 Find the greatest common factor (GCF/HCF)…
  11. x^3 , yx^2 Find the greatest common factor (GCF/HCF) of the following…
  12. 15a^3 , - 54a^2 , -150a Find the greatest common factor (GCF/HCF) of the…
  13. 2x^3y^2 ,-10x^2y^3 , 14xy Find the greatest common factor (GCF/HCF) of the…
  14. 14x^3y^5 ,-10x^5y^3 , 12x^2y^2 Find the greatest common factor (GCF/HCF) of the…
  15. 5a^5 + 10a^5 - 15a^2 Find the greatest common factor of the terms in each of…
  16. 2xyz+3x^2y+4y^2 Find the greatest common factor of the terms in each of the…
  17. 3a^2b^2 + 4b^2c^2 + 12a^2b^2c^2 Find the greatest common factor of the terms in…
Exercise 7.2
  1. 3x-9 Factorize the following:
  2. 5x-15x^2 Factorize the following:
  3. 20a^12b^2 - 15a^8b^4 Factorize the following:
  4. 72x^6y^7 - 96x^7y^6 Factorize the following:
  5. 20x^3 - 40x^2 + 80x Factorize the following:
  6. 2x^3y^2 - 4x^2y^3 + 8xy^4 Factorize the following:
  7. 10m^3n^2 + 15m^4n-20m^2n^3 Factorize the following:
  8. 2a^4b^4 - 3a^3b^5 + 4a^2b^5 Factorize the following:
  9. 28a^2 + 14a^2b^2 - 21a^4 Factorize the following:
  10. a^4b-3a^2b^2 - 6ab^3 Factorize the following:
  11. 2|^2mn-3|m^2n+4|mn^2 Factorize the following:
  12. x^4y^2 - x^2y^4 - x^4y^4 Factorize the following:
  13. 9x^2y+3axy Factorize the following:
  14. 16m-4m^2 Factorize the following:
  15. -4a^2 + 4ab-4ca Factorize the following:
  16. 16m-4m^2 Factorize the following:
  17. ax^2y+bxy^2 + cxyz Factorize the following:
Exercise 7.3
  1. 6x (2x-y) + 7y (2x-y) Factorize each of the following algebraic expressions:…
  2. 2r (y-z) + s (x-y) Factorize each of the following algebraic expressions:…
  3. 7a (2x-3) + 3b (2x-3) Factorize each of the following algebraic expressions:…
  4. 9a (6a-5b) - 12a^2 (6a-5b) Factorize each of the following algebraic…
  5. 5 (x-2y)^2 + 3 (x-2y) Factorize each of the following algebraic expressions:…
  6. 16 (21-3m)^2 - 12 (3m-2l) Factorize each of the following algebraic expressions:…
  7. 3a (x-2y) - b (x-2y) Factorize each of the following algebraic expressions:…
  8. a^2 (x+y) + b^2 (x+y) + c^2 (x+y) Factorize each of the following algebraic…
  9. (x-y)^2 + (x-y) Factorize each of the following algebraic expressions:…
  10. 6 (a+2b) - 4 (aa+2b)^2 Factorize each of the following algebraic expressions:…
  11. a (x-y) + 2b (y-x) + c (x-y)^2 Factorize each of the following algebraic…
  12. -4 (x-2y)^2 + 8 (x-2y) Factorize each of the following algebraic expressions:…
  13. x^3 (a-2b) + x^2 (a-2b) Factorize each of the following algebraic expressions:…
  14. (2x-3y) (a+b) + (3x-2y) (a+b) Factorize each of the following algebraic…
  15. 4 (x+y) (3a-b) + 6 (x+y) (2b-3a) Factorize each of the following algebraic…
Exercise 7.4
  1. qr-pr+qs-ps Factorize each of the following expressions:
  2. p^2q-pr^2 - pq+r^2 Factorize each of the following expressions:
  3. 1+x+xy+x^2y Factorize each of the following expressions:
  4. ax+ay-bx-by Factorize each of the following expressions:
  5. xa^2 + xb^2 - ya^2 - yb^2 Factorize each of the following expressions:…
  6. x^2 + xy+xzyz Factorize each of the following expressions:
  7. 2ax+bx+2ay+by Factorize each of the following expressions:
  8. ax-by-ay+y^2 Factorize each of the following expressions:
  9. axy+bcxy-az-bcz Factorize each of the following expressions:
  10. lm^2 - mn^2 - |m+n^2 Factorize each of the following expressions:…
  11. x^3 - y^2 + x-x^2y^2 Factorize each of the following expressions:…
  12. 6xy+6-9y-4x Factorize each of the following expressions:
  13. x^2 - 2ax-2ab+bx Factorize each of the following expressions:
  14. x^3 - 2x^2y+3xy^2 - 6y^3 Factorize each of the following expressions:…
  15. abx^2 + (ay-b) x-y Factorize each of the following expressions:
  16. (ax+by)^2 + (bx-ay)^2 Factorize each of the following expressions:…
  17. 16 (a-b)^3 - 24 (a-b)^2 Factorize each of the following expressions:…
  18. ab (x^2 + 1) + x (a^2 + b^2) Factorize each of the following expressions:…
  19. a^2x^2 + (ax^2 + 1) x+a Factorize each of the following expressions:…
  20. a (a-2b-c) + 2bc Factorize each of the following expressions:
  21. a (a+b-c) - bc Factorize each of the following expressions:
  22. x^2 - 11xy-x+11y Factorize each of the following expressions:
  23. ab - a - b + 1 Factorize each of the following expressions:
  24. x^2 + y-xy-x Factorize each of the following expressions:
Exercise 7.5
  1. 16x^2 - 25y^2 Factorize each of the following expressions:
  2. Factorize each of the following expressions: 27x^2 - 12y^2
  3. 144a^2 - 289b^2 Factorize each of the following expressions:
  4. 12m^2 - 27 Factorize each of the following expressions:
  5. 125x^2 - 45y^2 Factorize each of the following expressions:
  6. 144a^2 - 169b^2 Factorize each of the following expressions:
  7. (2a-b)^2 - 16c^2 Factorize each of the following expressions:
  8. (x+2y)^2 - 4 (2x-y)^2 Factorize each of the following expressions:…
  9. 3a^5 - 48a^3 Factorize each of the following expressions:
  10. a^4 - 16b^4 Factorize each of the following expressions:
  11. x^8 - 1 Factorize each of the following expressions:
  12. 64 - (a+1)^2 Factorize each of the following expressions:
  13. 361^2 - (m+n)^2 Factorize each of the following expressions:
  14. 25x^4y^4 - 1 Factorize each of the following expressions:
  15. a^4 - 1/b^4 Factorize each of the following expressions:
  16. x^3 - 144x Factorize each of the following expressions:
  17. (x-4y)^2 - 625 Factorize each of the following expressions:
  18. 9 (a-b)^2 - 100 (x-y)^2 Factorize each of the following expressions:…
  19. (3+2a)^2 - 25a^2 Factorize each of the following expressions:
  20. (x+y)^2 - (a-b)^2 Factorize each of the following expressions:
  21. 1/16 x^2y^2 - 4/49 y^2z^2 Factorize each of the following expressions:…
  22. 75a^3b^2 - 108ab^4 Factorize each of the following expressions:
  23. x^5 - 16x^3 Factorize each of the following expressions:
  24. 50/x^2 - 2x^2/81 Factorize each of the following expressions:
  25. 256x^5 - 81x Factorize each of the following expressions:
  26. a^4 - (2b+c)^4 Factorize each of the following expressions:
  27. (3x+4y)^4 - x^4 Factorize each of the following expressions:
  28. p^2q^2 - p^4q^4 Factorize each of the following expressions:
  29. 3x^3y-24xy^3 Factorize each of the following expressions:
  30. a^4b^4 - 16c^4 Factorize each of the following expressions:
  31. x^4 - 625 Factorize each of the following expressions:
  32. x^4 - 1 Factorize each of the following expressions:
  33. 49 (a-b)^2 - 25 (a+b)^2 Factorize each of the following expressions:…
  34. x-y-x^2 + y^2 Factorize each of the following expressions:
  35. 16 (2x-1)^2 - 25y^2 Factorize each of the following expressions:
  36. 4 (xy+1)^2 - 9 (x-1)^2 Factorize each of the following expressions:…
  37. (2x+1)^2 - 9x^4 Factorize each of the following expressions:
  38. x^4 - (2y-3z)^2 Factorize each of the following expressions:
  39. a^2 - b^2 + a-b Factorize each of the following expressions:
  40. 16a^4 - b^4 Factorize each of the following expressions:
  41. a^4 - 16 (b-c)^4 Factorize each of the following expressions:
  42. 2a^4 - 32a Factorize each of the following expressions:
  43. a^4b^4 - 81c^4 Factorize each of the following expressions:
  44. xy^9 - yx^9 Factorize each of the following expressions:
  45. x^3 - x Factorize each of the following expressions:
  46. 18^2x^2 - 32 Factorize each of the following expressions:
Exercise 7.6
  1. 4x^2 + 12xy+9y^2 Factorize each of the following algebraic expressions:…
  2. 9a^2 - 24ab+16b^2 Factorize each of the following algebraic expressions:…
  3. p^2q^2 - 6pqr+9r^2 Factorize each of the following algebraic expressions:…
  4. 36a^2 + 36a+9 Factorize each of the following algebraic expressions:…
  5. a^2 + 2ab+b^2 - 16 Factorize each of the following algebraic expressions:…
  6. 9z^2 - x^2 + 4xy-4y^2 Factorize each of the following algebraic expressions:…
  7. 9a^4 - 24a^2b^2 + 16b^4 - 256 Factorize each of the following algebraic…
  8. 16-a^6 + 4a^3b^3 - 4b^6 Factorize each of the following algebraic expressions:…
  9. a^2 - 2ab+b^2 - c^2 Factorize each of the following algebraic expressions:…
  10. x^2 + 2x+1-9y^2 Factorize each of the following algebraic expressions:…
  11. a^2 + 4ab+3b^2 Factorize each of the following algebraic expressions:…
  12. 96-4x-x^2 Factorize each of the following algebraic expressions:
  13. a^4 + 3a^2 + 4 Factorize each of the following algebraic expressions:…
  14. 4x^4 + 1 Factorize each of the following algebraic expressions:
  15. 4x^4 + y^4 Factorize each of the following algebraic expressions:…
  16. (x+2)^2 - 6 (x+2) + 9 Factorize each of the following algebraic expressions:…
  17. 25-p^2 - q^2 - 2pq Factorize each of the following algebraic expressions:…
  18. x^2 + 9y^2 - 6xy-25a^2 Factorize each of the following algebraic expressions:…
  19. 49-a^2 +8ab-16b^2 Factorize each of the following algebraic expressions:…
  20. a^2 - 8ab+16b^2 - 25c^2 Factorize each of the following algebraic expressions:…
  21. x^2 - y^2 + 6y-9 Factorize each of the following algebraic expressions:…
  22. 25x^2 - 10x+1-36y^2 Factorize each of the following algebraic expressions:…
  23. a^2 - b^2 + 2bc-c^2 Factorize each of the following algebraic expressions:…
  24. a^4 + 2b+b^2 - c^2 Factorize each of the following algebraic expressions:…
  25. 49-x^2 - y^2 + 2xy Factorize each of the following algebraic expressions:…
  26. a^2 + 4b^2 - 4ab-4c^2 Factorize each of the following algebraic expressions:…
  27. x^2 -y^2 -4xz+4z^2 Factorize each of the following algebraic expressions:…
Exercise 7.7
  1. x^2 + 12x-45 Factorize each of the following algebraic expressions:…
  2. 40+3x-x^2 Factorize each of the following algebraic expressions:
  3. a^2 + 3a-88 Factorize each of the following algebraic expressions:…
  4. a^2 - 14a-51 Factorize each of the following algebraic expressions:…
  5. x^2 + 14x+45 Factorize each of the following algebraic expressions:…
  6. x^2 - 22x+120 Factorize each of the following algebraic expressions:…
  7. x^2 - 11x-42 Factorize each of the following algebraic expressions:…
  8. a^2 + 2a-3 Factorize each of the following algebraic expressions:…
  9. a^2 + 14a+48 Factorize each of the following algebraic expressions:…
  10. x^2 - 4x-21 Factorize each of the following algebraic expressions:…
  11. y^2 + 5y-36 Factorize each of the following algebraic expressions:…
  12. (a^2 - 5a)^2 - 36 Factorize each of the following algebraic expressions:…
  13. (a+7) (a-10) + 16 Factorize each of the following algebraic expressions:…
Exercise 7.8
  1. 2x^2 + 5x+3 Resolve each of the following quadratic trinomials into factors:…
  2. 2x^2 - 3x-2 Resolve each of the following quadratic trinomials into factors:…
  3. 3x^2 + 10x+3 Resolve each of the following quadratic trinomials into factors:…
  4. 7x-6-2x^2 Resolve each of the following quadratic trinomials into factors:…
  5. 7x^2 - 19x-6 Resolve each of the following quadratic trinomials into factors:…
  6. 28-31x-5x^2 Resolve each of the following quadratic trinomials into factors:…
  7. 3+23y-8y^2 Resolve each of the following quadratic trinomials into factors:…
  8. 11x^2 - 54x+63 Resolve each of the following quadratic trinomials into factors:…
  9. 7x-6x^2 + 20 Resolve each of the following quadratic trinomials into factors:…
  10. 3x^2 + 22x+35 Resolve each of the following quadratic trinomials into factors:…
  11. 12x^2 - 17xy+6y^2 Resolve each of the following quadratic trinomials into…
  12. 6x^2 - 5xy-6y^2 Resolve each of the following quadratic trinomials into…
  13. 6x^2 - 13xy + 2y^2 Resolve each of the following quadratic trinomials into…
  14. 14x^2 + 11xy-15y^2 Resolve each of the following quadratic trinomials into…
  15. 6a^2 + 17ab-3b^2 Resolve each of the following quadratic trinomials into…
  16. 36a^2 + 12abc-15b^2c^2 Resolve each of the following quadratic trinomials into…
  17. 15x^2 - 16xyz-15y^2z^2 Resolve each of the following quadratic trinomials into…
  18. (x-2y)^2 - 5 (x-2y) + 6 Resolve each of the following quadratic trinomials into…
  19. (2a-b)^2 + 2 (2a-b) - 8 Resolve each of the following quadratic trinomials into…
Exercise 7.9
  1. p^2 + 6p+8 Factorize each of the following quadratic polynomials by using the…
  2. q^2 - 10q+21 Factorize each of the following quadratic polynomials by using the…
  3. 4y^2 + 12y+5 Factorize each of the following quadratic polynomials by using the…
  4. p^2 + 6p-16 Factorize each of the following quadratic polynomials by using the…
  5. x^2 + 12x+20 Factorize each of the following quadratic polynomials by using the…
  6. a^2 - 14a-51 Factorize each of the following quadratic polynomials by using the…
  7. a^2 + 2a-3 Factorize each of the following quadratic polynomials by using the…
  8. 4x^2 - 12x+5 Factorize each of the following quadratic polynomials by using the…
  9. y^2 - 7y+12 Factorize each of the following quadratic polynomials by using the…
  10. z^2 - 4z-12 Factorize each of the following quadratic polynomials by using the…

Exercise 7.1
Question 1.

Find the greatest common factor (GCF/HCF) of the following polynomials



Answer:

The numerical coefficients of given numerical are 2, 12

Greatest common factor of 2, 12 is 2


Common literals appearing in given numerical is x


Smallest power of x in two monomials = 2


Monomials of common literals with smallest power= x2


Hence, the greatest common factor = 2x2



Question 2.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 6,18

Greatest common factor of 6, 18 is 6


Common literals appearing in given numerical are x and y


Smallest power of x in both monomials= 2


Smallest power of y in both monomials = 1


Binomials of common literals with smallest power= x2y


Hence, the greatest common factor = 6x2y


Question 3.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 7, 21, 14

Greatest common factor of 7, 21, 14 is 7


Common literals appearing in given numerical are x and y


Smallest power of x in three monomials = 1


Smallest power of y in three monomials = 0


Monomials of common literals with smallest power= x


Hence, the greatest common factor = 7x



Question 4.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 42 and 63.

Greatest common factor of 42, 63 is 21.


Common literals appearing in given numerical are x, y and z


Smallest power of x in two monomials = 2


Smallest power of y in two monomials = 1


Smallest power of z in two monomials = 1


Monomials of common literals with smallest power= x2yz


Hence, the greatest common factor = 21x2yz



Question 5.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 12, 6, 2

Greatest common factor of 12, 6, 2 is 2.


Common literals appearing in given numerical are a and x


Smallest power of x in three monomials = 2


Smallest power of a in three monomials = 1


Monomials of common literals with smallest power= ax2


Hence, the greatest common factor = 2ax2



Question 6.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 9, 15, 16, 21

Greatest common factor of 9, 15, 16, 21 is 3.


Common literals appearing in given numerical are x and y


Smallest power of x in four monomials = 1


Smallest power of y in four monomials = 0


Monomials of common literals with smallest power= x


Hence, the greatest common factor = 3x



Question 7.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 4, -12, 18.

Greatest common factor of 4, -12, 18 is 2.


Common literals appearing in given numerical are a and b


Smallest power of a in three monomials = 2


Smallest power of b in three monomials = 1


Monomials of common literals with smallest power= a2b


Hence, the greatest common factor = 2a2b



Question 8.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 6, 9, 3

Greatest common factor of 6, 9, 3 is 3.


Common literals appearing in given numerical are x and y


Smallest power of x in three monomials = 1


Smallest power of y in three monomials = 2


Monomials of common literals with smallest power= xy2


Hence, the greatest common factor = 3xy2



Question 9.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 0

Common literals appearing in given numerical are a and b


Smallest power of a in two monomials = 2


Smallest power of b in two monomials = 2


Monomials of common literals with smallest power= the greatest common factor = a2b2



Question 10.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 36, 54, 90

Greatest common factor of 36, 54, 90 is 18.


Common literals appearing in given numerical are a, b and c


Smallest power of a in three monomials = 2


Smallest power of b in three monomials = 0


Smallest power of c in three monomials = 2


Monomials of common literals with smallest power= a2c2


Hence, the greatest common factor = 18a2c2



Question 11.

Find the greatest common factor (GCF/HCF) of the following polynomials:

x3, yx2


Answer:

The numerical coefficients of given numerical are 0

Common literals appearing in given numerical are x and y


Smallest power of x in two monomials = 2


Smallest power of y in two monomials = 0


Monomials of common literals with smallest power= x2


Hence, the greatest common factor = x2



Question 12.

Find the greatest common factor (GCF/HCF) of the following polynomials:

15a3, - 54a2, -150a


Answer:

The numerical coefficients of given numerical are 15, -45, -150

Greatest common factor of 15, -45, -150 is 15.


Common literals appearing in given numerical is smallest power of a in three monomials = 1


Monomials of common literals with smallest power= a


Hence, the greatest common factor = 15a



Question 13.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 2, 10, 14.

Greatest common factor of 2, 10, 14 is 2.


Common literals appearing in given numerical are x and y


Smallest power of x in three monomials = 1


Smallest power of y in three monomials = 1


Monomials of common literals with smallest power= xy


Hence, the greatest common factor = 2xy



Question 14.

Find the greatest common factor (GCF/HCF) of the following polynomials:



Answer:

The numerical coefficients of given numerical are 14, 10, 2.

Greatest common factor of 14, 10, 2 is 2.


Common literals appearing in given numerical are x and y


Smallest power of x in three monomials = 2


Smallest power of y in three monomials = 2


Monomials of common literals with smallest power= x2y2


Hence, the greatest common factor = 2x2y2



Question 15.

Find the greatest common factor of the terms in each of the following expressions:



Answer:

The highest common factor of three terms = 5a2

=5a2(a2 + 2a -3)



Question 16.

Find the greatest common factor of the terms in each of the following expressions:



Answer:

The highest common factor of three terms = y

Therefore,


= y(2xz + 3x2 +4y)



Question 17.

Find the greatest common factor of the terms in each of the following expressions:



Answer:

The highest common factor of three terms = b2

Therefore,


5a2b2 + 4b2c2 + 12a2b2c2 = b2(3a2 + 4c2 + 12a2c2)




Exercise 7.2
Question 1.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 3x and -9 of expression 3x - 9 is 3

3x = 3 × x and -9 = 3 × (-3)


3x - 9 = 3(x - 3)


Question 2.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 5x and -15x2 of expression 5x - 15x2 is 5x -15x2

5x = 5x(1) and -15x2= 5x(-3x)


5x -15x2 = 5x(1 - 3x)



Question 3.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 20a12b2 and -15a8b4 of expression 20a12b2 - 15a8b4 is 5a8b2

20a12b2 = 5a8b2 (4a4) and - 15a8b4 = 5a8b2 (-3b2)


20a12b2 - 15a8b4 = 5a8b2 (4a4 - 3b2)

= 5a8b2((2a)2 - (b√3)2)

= 5a8b2(2a + b√3)(2a - b√3)


Question 4.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 72x6y7 and - 96x7y6 of expression 72x6y7 - 96x7y6 is 24x6y6

72x6y7 = 24x6y6 (3y) and - 96x7y6 = 24x6y6(-4x)


72x6y7 - 96x7y6 = 24x6y6 (3y - 4y)



Question 5.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 20x3, -40x2 and 80x of expression 20x3 - 40x2 + 80x is 20x

20x3 - 40x2 + 80x= 20x(x2 - 2x +4)



Question 6.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 2x3y2, - 4x2y3, - 8xy4 of expression 2x3y2 - 4x2y3 - 8xy4 is 2xy2

2x3y2 - 4x2y3 - 8xy4 = 2xy2 (x2 - 2xy + 4y)



Question 7.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 10m3n2, 15m4n, - 20m2n3 of expression 10m3n2 + 15m4n - 20m2n3 is 5mn2

10m3n2 + 15m4n - 20m2n3 = 5mn2(2mn + 3m2 - 4n)



Question 8.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 2a4b4, - 3a3b5, 4a2b5 of expression 2a4b4 - 3a3b5 + 4a2b5 is a2b4

2a4b4 - 3a3b5 + 4a2b5 = a2b4 (2a2 - 3ab + 4b)



Question 9.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 28a2, 14a2b2, - 21a4 of expression 28a2 + 14a2b2 - 21a4 is 7a2

28a2 + 14a2b2-21a4 = 7a2(4 + 2b2 - 3a2)



Question 10.

Factorize the following:



Answer:

Greatest common factor of the two terms namely a4b, - 3a2b2, - 6ab3 of expression a4b - 3a2b2 - 6ab3 is ab

a4b - 3a2b2 - 6ab3 = ab (a3 - 3ab -6ab2)



Question 11.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 21lmn, - 3lm2n, 4lmn2 of expression 21lmn - 3lm2n + 4lmn2 is lm

21lmn - 3lm2n + 4lmn2 = lm(21 - 3m + 4n)



Question 12.

Factorize the following:



Answer:

Greatest common factor of the two terms namely x4y2, - x2y4, - x4y4 of expression x4y2 - x2y4 - x4 y4 is x2y2

x4y2 - x2y4 - x4y4 = x2y2 (x2 - y2 -x2y2)



Question 13.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 9x2y and 3axy of expression 9x2y + 3axy is 3xy

9x2y + 3axy = 3xy(3x2 +a)



Question 14.

Factorize the following:



Answer:

Greatest common factor of the two terms namely 16m - 4m2 of expression 16m - 4m2 is 4m

16m - 4m2 = 4m(4 - m)



Question 15.

Factorize the following:



Answer:

Greatest common factor of the two terms namely -4a, 4ab, -4ca of expression -4a + 4ab -4ca is -4a

-4a + 4ab -4ca = -4a(a - b + c)



Question 16.

Factorize the following:



Answer:

Greatest common factor of the two terms namely x2yz, xy2z, xyz2 of expression x2yz + xy2z + xyz2 is xyz

x2yz + xy2z + xyz2 = xyz(x + y +z)



Question 17.

Factorize the following:



Answer:

Greatest common factor of the two terms namely -4a, 4ab, -4ca of expression -4a + 4ab -4ca is -4a

ax2y + bxy2 + cxyz = xy (ax + by + cz)




Exercise 7.3
Question 1.

Factorize each of the following algebraic expressions:



Answer:

(6x + 7y) (2x – y) [Therefore, taking (2x – y) common)]



Question 2.

Factorize each of the following algebraic expressions:



Answer:

-2r (x – y) + s (x – y) [Therefore, taking – 1 common]

= (x – y) (-2r + s) [Therefore, taking (x – y) common]


= (x – y) (s – 2r)



Question 3.

Factorize each of the following algebraic expressions:



Answer:

(7a + 3b) (2x – 3) [Therefore, taking (2x – 3) common]



Question 4.

Factorize each of the following algebraic expressions:



Answer:

(9a – 12a2) (6a – 5b) [Therefore, taking (6a – 5b) common]



Question 5.

Factorize each of the following algebraic expressions:



Answer:

(x – 2y) [5 (x – 2y) + 3] [Therefore, taking (x – 2y) common]

= (x – 2y) (5x – 10y + 3)



Question 6.

Factorize each of the following algebraic expressions:



Answer:

16 (2l – 3m2) + 12 (2l – 3m) [Therefore, 3m – 2l = - (2l – 3m)]

= 4 (2l – 3m) [4 (2l – 3m) + 3] [Therefore, taking 4 (2l – 3m) common]


= 4 (3l – 2m) (8l – 12m + 3)



Question 7.

Factorize each of the following algebraic expressions:



Answer:

(3a – b) (x – 2y) [Therefore, taking (x – 2y) as common]



Question 8.

Factorize each of the following algebraic expressions:



Answer:

(a2 + b2 + c2) (x + y) [Therefore, taking (x + y) common in each term]



Question 9.

Factorize each of the following algebraic expressions:



Answer:

(x – y) (x – y + 1) [Therefore, taking (x – y) common)



Question 10.

Factorize each of the following algebraic expressions:



Answer:

[6 – 4 (a + 2b)] (a + 2b) [Therefore, taking (a + 2b) common]

= (6 – 4a – 8b) (a + 2b)



Question 11.

Factorize each of the following algebraic expressions:



Answer:

a (x – y) – 2b (x – y) + c (x – y)2 [Therefore, (y – x) = - (x – y)]

= (x – y) [a – 2b + c (x – y)]


= (x – y) (a – 2b + cx – cy)



Question 12.

Factorize each of the following algebraic expressions:



Answer:

- (x – 2y) [4 (x – 2y – 8] [Therefore, taking – (x – 2y) as common]

= - (x – 2y) (4x – 8y – 8)



Question 13.

Factorize each of the following algebraic expressions:



Answer:

x2 (a – 2b) (x + 1) [Therefore, taking x2 (a – 2b) as common]



Question 14.

Factorize each of the following algebraic expressions:



Answer:

(a + b) (2x – 3y + 3x – 2y) [Therefore, taking (a + b) common]

= (a + b) (5x – 5y)



Question 15.

Factorize each of the following algebraic expressions:



Answer:

2 (x + y) [2 (3a – b) + 3 (2b – 3a)] [Therefore, by taking 2 (x + y) common]

= 2 (x + y) (4b – 3a)




Exercise 7.4
Question 1.

Factorize each of the following expressions:



Answer:

q (r + s) – p (r + s)

= (q – p) (r + s)



Question 2.

Factorize each of the following expressions:



Answer:

p (pq – r2) – 1 (pq – r2)

= (p – 1) (pq – r2)



Question 3.

Factorize each of the following expressions:



Answer:

1 (1 + xy) + x (1 + xy)

= (1 + x) (1 + xy)



Question 4.

Factorize each of the following expressions:



Answer:

a (x + y) – b (x + y)

= (a – b) (x + y)



Question 5.

Factorize each of the following expressions:



Answer:

x (a2 + b2) – y (a2 + b2)

= (x – y) (a2 + b2)



Question 6.

Factorize each of the following expressions:



Answer:

x (x + 3) + y (x + 3)

= (x + y) (x + 3)



Question 7.

Factorize each of the following expressions:



Answer:

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

= (2a + b) (x + y)



Question 8.

Factorize each of the following expressions:



Answer:

a (b – y) – y (b – y)

= (a – y) (b – y)



Question 9.

Factorize each of the following expressions:



Answer:

a (xy – z) + bc (xy – z)

= (a + bc) (xy – z)



Question 10.

Factorize each of the following expressions:



Answer:

2m (m – 1) – n2 (m – 1)

= (2m – n2) (m – 1)



Question 11.

Factorize each of the following expressions:



Answer:

y2 (1 + x2) + x (1 + x2)

= (x – y2) (1 + x2)



Question 12.

Factorize each of the following expressions:



Answer:

2x (3y – 2) – 3 (3y – 2)

= (2x – 3) (3y – 2)



Question 13.

Factorize each of the following expressions:



Answer:

x (x + b) – 2a (x + b)

= (x – 2a) (x + b)



Question 14.

Factorize each of the following expressions:



Answer:

x (x2 + 3y2) – 2y (x2 + 3y2)

=(x – 2y) (x2 + 3y2)



Question 15.

Factorize each of the following expressions:



Answer:

abx2 – ayx – bx – y

= bx (ax – 1) + y (ax – 1)


= (bx + y) (ax – 1)



Question 16.

Factorize each of the following expressions:



Answer:

a2x2 + b2y2 + 2axby + b2x2 + a2y2 – 2axby

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


= (a2 + b2) (x2 + y2)



Question 17.

Factorize each of the following expressions:



Answer:

8 (a – b)2 [2 (a – b) – 3]

= 8 (a – b)2 [2a – 2b – 3]



Question 18.

Factorize each of the following expressions:



Answer:

abx2 + ab + xa2 + xb2

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


= (ax + b) (bx + a)



Question 19.

Factorize each of the following expressions:



Answer:

a2x2 + ax3 + x + a

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


= (x + a) (ax2 + 1)



Question 20.

Factorize each of the following expressions:



Answer:

a2 – 2ab – ac + 2bc

= a (a – c) – 2b (a – c)


= (a – 2b) (a – c)



Question 21.

Factorize each of the following expressions:



Answer:

a2 + ab + ac – bc

= a (a – c) + b (a – c)


= (a + b) (a – c)



Question 22.

Factorize each of the following expressions:



Answer:

x (x – 1) – 11y (x – 1)

= (x – 11y) (x – 1)



Question 23.

Factorize each of the following expressions:

ab – a – b + 1


Answer:

a (b – 1) – 1 (b – 1)

= (a – 1) (b – 1)



Question 24.

Factorize each of the following expressions:



Answer:

x (x – 1) – y (x – 1)

= (x – y) (x – 1)




Exercise 7.5
Question 1.

Factorize each of the following expressions:



Answer:

(4x)2 – (5y)2

= (4x + 5y) (4x – 5y)



Question 2.

Factorize each of the following expressions:



Answer:

Consider 27x2 - 12y2,

Taking 3 common we get,

3 [(3x)2 – (2y)2]

As we know a2 - b2 = (a-b) (a+b)

= 3 (3x + 2y) (3x – 2y)


Question 3.

Factorize each of the following expressions:



Answer:

(12a)2 – (17b)2

= (12a + 17b) (12a – 17b)



Question 4.

Factorize each of the following expressions:



Answer:

3 (4m2 – 9)

= 3 [(2m)2 – 32]


= 3 (2m + 3) (2m – 3)



Question 5.

Factorize each of the following expressions:



Answer:

5 (25x2 – 9y2)

= 5 [(5x)2 – (3y)2]


= 5 (5x + 3y) (5x – 3y)



Question 6.

Factorize each of the following expressions:



Answer:

(12a)2 – (13b)2

= (12a + 13b) (12a – 13b)



Question 7.

Factorize each of the following expressions:



Answer:

(2a – b)2 – (4c)2

= (2a – b + 4c) (2a – b – 4c)



Question 8.

Factorize each of the following expressions:



Answer:

(x + 2y)2 – [2 (2x – y)]2

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


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


= (5x) (4y – 3x)



Question 9.

Factorize each of the following expressions:



Answer:

3a3 (a2 – 16)

= 3a3 (a2 – 42)


= 3a3 (a + 4) (a – 5)



Question 10.

Factorize each of the following expressions:



Answer:

(a2)2 – (4b2)2

= (a2 + 4b2) (a2 – 4b2)



Question 11.

Factorize each of the following expressions:



Answer:

(x4)2–(1)2

= (x4 + 1) (x4 – 1)



Question 12.

Factorize each of the following expressions:



Answer:

82 – (a + 1)2

= [8 + (a + 1)] [8 – (a + 1)]


= (a + 9) (7 – a)



Question 13.

Factorize each of the following expressions:



Answer:

(6l)2 – (m + n)2

= (6l + m + n) (6l – m – n)



Question 14.

Factorize each of the following expressions:



Answer:

(5x2y2)2 – (1)2

= (5x2y2 – 1) (5x2y2 + 1)



Question 15.

Factorize each of the following expressions:



Answer:

(a2)2 – ()2

= (a2 + ) (a2 - )



Question 16.

Factorize each of the following expressions:



Answer:

x [x2 – (12)2]

= x (x + 12) (x – 12)



Question 17.

Factorize each of the following expressions:



Answer:

(x – 4y)2 – (25)2

= (x – 4y + 25) (x – 4y – 25)



Question 18.

Factorize each of the following expressions:



Answer:

[3 (a – b)]2 – [10 (x – y)]2

= [3 (a – b) + 10 (x + y)] [3 (a – b) – 10 (x – y)]


= [3a – 3b + 10x – 10y] [3a – 3b – 10x + 10y]



Question 19.

Factorize each of the following expressions:



Answer:

(3 + 2a)2 – (5a)2

= (3 + 2a + 5a) (3 + 2a – 5a)


= (7a + 3) (3 – 3a)



Question 20.

Factorize each of the following expressions:



Answer:

[(x + y) + (a – b)] [(x + y) – (a – b)]

= (x + y + a – b) (x + y – a + b)



Question 21.

Factorize each of the following expressions:



Answer:

(xy)2 – (yz)2

= ( + ) ( - )


= y2 ( + z) ( - z)



Question 22.

Factorize each of the following expressions:



Answer:

3ab2 (25a2 – 36b2)

= 3ab2 [(5a)2 – (6b)2]


= 3ab2 (5a + 6b) (5a – 6b)



Question 23.

Factorize each of the following expressions:



Answer:

x3 (x2 – 16)

= x3 (x2 – 42)


= x3 (x + 4) (x – 4)



Question 24.

Factorize each of the following expressions:



Answer:

2 (- )

= 2 [()2 – ()2]


= 2 (+ ) ( - )



Question 25.

Factorize each of the following expressions:



Answer:

x (256x4 – 81)

= x [(16x2)2 – 92]


= x (16x + 9) (16x – 9)



Question 26.

Factorize each of the following expressions:



Answer:

(a2)2 – [(2b + c)2]2

= [a2 + (2b + c)2] [a2 – (2b + c)2]


= [a2 + (2b + c)2] [a + 2b + c] [a – 2b – c]



Question 27.

Factorize each of the following expressions:



Answer:

[(3x + 4y)2]2 – (x2)2

= [(3x + 4y)2 + x2] [(3x + 4y)2 – x2]


= [(3x + 4y)2 + x2] [3x + 4y + x] [3x + 4y – x]



Question 28.

Factorize each of the following expressions:



Answer:

(pq)2 – (p2q2)2

= (pq + p2q2) (pq – p2q2)


= (pq)2 (1 + pq) (1 – pq)



Question 29.

Factorize each of the following expressions:



Answer:

3xy (x2 – 81y2)

= 3xy [x2 – (9y)2]


= (3xy) (x + 9y) (x – 9y)



Question 30.

Factorize each of the following expressions:



Answer:

(a2b2)2 – (4c2)2

= (a2b2 + 4c2) (a2b2 – 4c2)


= (a2b2 + 4c2) (ab + 2c) (ab – 2c)



Question 31.

Factorize each of the following expressions:



Answer:

(x2)2 – (25)2

= (x2 + 25) (x2 – 25)


= (x2 + 25) (x + 5) (x – 5)



Question 32.

Factorize each of the following expressions:



Answer:

(x2)2 – (1)2

= (x2 + 1) (x2 – 1)


= (x2 + 1) (x + 1) (x – 1)



Question 33.

Factorize each of the following expressions:



Answer:

[7 (a – b)]2 – [5 (a + b)]2

= [7 (a – b) + 5 (a + b)] [7 (a – b) – 5 (a + b)]


= (7a – 7b + 5a + 5b) (7a – 7b – 5a – 5b)


= (12a – 2b) (2a – 12b)


= 2 (6a – b) 2 (a – 6b)


= 4 (6a – b) (a – 6b)



Question 34.

Factorize each of the following expressions:



Answer:

x – y – (x2 – y2)

= x – y – (x + y) (x – y)


= (x – y) (1 – x – y)



Question 35.

Factorize each of the following expressions:



Answer:

[4 (2x – 1)]2 – (5y)2

= (8x – 4 + 5y) (8x – 4 – 5y)



Question 36.

Factorize each of the following expressions:



Answer:

[2x (xy + 1)]2 – [3 (x – 1)]2

= (2xy + 2 + 3x – 3) (2xy + 2 – 3x + 3)


= (2xy + 3x – 1) (2xy – 3x + 5)



Question 37.

Factorize each of the following expressions:



Answer:

(2x + 1)2 – (3x2)2

= (2x + 1 + 3x2) (2x + 1 – 3x2)


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



Question 38.

Factorize each of the following expressions:



Answer:

(x2)2 – (2y – 3z)2

= (x2 + 2y – 3z) (x2 – 2y + 3z)



Question 39.

Factorize each of the following expressions:



Answer:

(a + b) (a – b) + (a – b)

= (a – b) (a + b + 1)



Question 40.

Factorize each of the following expressions:



Answer:

(4a2)2 – (b2)2

= (4a2 + b2) (4a2 – b2)


= (4a2 + b2) (2a + b) (2a – b)



Question 41.

Factorize each of the following expressions:



Answer:

(a2)2 – [4 (b – c)2]

= [a2 + 4 (b – c)2] [a2 – 4 (b – c)2]


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



Question 42.

Factorize each of the following expressions:



Answer:

2a (a4 – 16)

= 2a [(a)2 – (4)2]


= 2a (a2 + 4) (a2 – 4)


= 2a (a2 + 4) (a + 2) (a – 2)



Question 43.

Factorize each of the following expressions:



Answer:

(a2b2)2 – (9c2)2

= (a2b2 + 9c2) (a2b2 – 9c2)


= (a2b2 + 9c2) (ab + 3c) (ab – 3c)



Question 44.

Factorize each of the following expressions:



Answer:

xy (y8 – x8)

= xy [(y4)2 – (x4)2]


= xy (y4 + x4) (y4 – x4)


= xy (y4 + x4) (y2 + x2) (y2 – x2)


= xy (y4 + x4) (y2 + x2) (y + x) (y – x)



Question 45.

Factorize each of the following expressions:



Answer:

x (x2 – 1)

= x (x + 1) (x – 1)



Question 46.

Factorize each of the following expressions:



Answer:

2 [(3ax)2 – (4)2]

= 2 (3ax + 4) (3ax – 4)




Exercise 7.6
Question 1.

Factorize each of the following algebraic expressions:



Answer:

4x2 + 12xy + 9y2

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


= (2x + 3y)2



Question 2.

Factorize each of the following algebraic expressions:



Answer:

Consider 9a2 – 24ab + 16b2,

As we know (x - y)2 = x2 + y2 - 2xy

Here x = 3a, y = 4b

So,

(3a)2 + (4b)2 – 2 (3a) (4a)

= (3a – 4b)2


Question 3.

Factorize each of the following algebraic expressions:



Answer:

(pq)2 + (3r)2 – 2 (pq) (3r)

= (pq – 3r)2



Question 4.

Factorize each of the following algebraic expressions:



Answer:

9 (4a2 + 4a + 1)

= 9 [(2a)2 + 2 (2a) + 11]


= 9 (2a + 1)2



Question 5.

Factorize each of the following algebraic expressions:



Answer:

(a + b)2 - 42

= (a + b + 4) (a + b – 4)



Question 6.

Factorize each of the following algebraic expressions:



Answer:

(3z)2 – [x2 – 2 (x) (2y) + (2y)2]

= (3z)2 – (x – 2y)2


= [3z + (x – 2y)] [3z – (x – 2y)]



Question 7.

Factorize each of the following algebraic expressions:



Answer:

(3a2)2 – 2 (4a2) (3b2) + (4b2)2 – (16)2

= (3a2 – 4b2)2 – (16)2


= (3a2 – 4b2 + 16) (3a2 – 4b2 – 16)



Question 8.

Factorize each of the following algebraic expressions:



Answer:

42 – [(a3)2 – 2 (a3) (2b3) + (2b3)2]

= 42 – (a3 – 2b3)2


= [4 + (a3 – 2b3)] [4 – (a3 – 2b3)]



Question 9.

Factorize each of the following algebraic expressions:



Answer:

(a + b)2 – c2

= (a + b + c) (a + b – c)



Question 10.

Factorize each of the following algebraic expressions:



Answer:

(x + 1)2 – (3y)2

= (x + 3y + 1) (x – 3y + 1)



Question 11.

Factorize each of the following algebraic expressions:



Answer:

a2 + ab + 3ab + 3b2

= a (a + b) + 3b (a + b)


= (a + 3b) (a + b)



Question 12.

Factorize each of the following algebraic expressions:



Answer:

-x2 – 4x + 96

= -x2 – 12x + 8x + 96


= -x (x + 12) + 8 (x + 12)


= (x + 12) (-x + 8)



Question 13.

Factorize each of the following algebraic expressions:



Answer:

(a2)2 + (a2)2 + 2 (2a2) + 4 – a2

= (a2 + 2)2 + (-a2)


= (a2 + 2 + a) (a2 + 2 – a)



Question 14.

Factorize each of the following algebraic expressions:



Answer:

(2x2)2 + 1 + 4x2 – 4x2

= (2x2 + 1)2 – 4x2


= (2x2 + 2x + 1) (2x2 – 2x + 1)



Question 15.

Factorize each of the following algebraic expressions:



Answer:

(2x2)2 + (y2)2 + 4x2y2 – 4x2y2

= (2x2 + y2)2 – 4x2y2


= (2x2 + y2 + 2xy) (2x2 + y2 – 2xy)



Question 16.

Factorize each of the following algebraic expressions:



Answer:

x2 + 4 + 4x – 6x – 12 + 9

= x2 + 1 – 2x


= (x – 1)2



Question 17.

Factorize each of the following algebraic expressions:



Answer:

25 – (p2 + q2 + 2pq)

= (5)2 – (p + q)2


= (5 + p + q) (5 –p – q)


= - (p + q – 5) (p + q + 5)



Question 18.

Factorize each of the following algebraic expressions:



Answer:

(x – 3y)2 – (5a)2

= (x – 3y + 5a) (x – 3y – 5a)



Question 19.

Factorize each of the following algebraic expressions:



Answer:

49 – (a2 – 8ab + 16b2)

= 49 – (a – 4b)2

We know:
a2 – b2 = (a + b)(a-b)

= (7 + a – 4b) (7 – a + 4b)


= - (a – 4b + 7) (a – 4b – 7)


Question 20.

Factorize each of the following algebraic expressions:



Answer:

(a – 4b)2- (5c)2

= (a – 4b + 5c) (a – 4b – 5c)



Question 21.

Factorize each of the following algebraic expressions:



Answer:

x2 + 6y – (y2 – 6y + 9)

= x2 – (y – 3)2


= (x + y – 3) (x – y + 3)



Question 22.

Factorize each of the following algebraic expressions:



Answer:

(5x)2 – 2 (5x) + 1 – (6y)2

= (5x – 1)2 – (6y)2


= (5x – 1 + 6y) (5x – 1 – 6y)



Question 23.

Factorize each of the following algebraic expressions:



Answer:

a2 – (b2 – 2bc + c2)

= a2 – (b – c)2


= (a + b – c) (a – b + c)



Question 24.

Factorize each of the following algebraic expressions:



Answer:

(a + b)2 – c2

= (a + b + c) (a + b – c)



Question 25.

Factorize each of the following algebraic expressions:



Answer:

49 – (x2 + y2 – 2xy)

= 72 – (x – y)2


= [7 + (x – y)] [7 – x + y]



Question 26.

Factorize each of the following algebraic expressions:



Answer:

a2 – 2 (a) (2b) + (2b)2 – (2c)2

= (a – 2b)2 – (2c)2


= (a – 2b + 2c) (a – 2b – 2c)



Question 27.

Factorize each of the following algebraic expressions:



Answer:

x2 – 2 (x) (2z) + (2z)2 – y2

As (a-b)2 = a2 + b2 – 2ab

= (x – 2z)2 – y2

As a2 – b2 = (a+b)(a-b)

= (x – 2z + y) (x – 2z – y)



Exercise 7.7
Question 1.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = 12, pq = -45


Clearly,


15 – 3 = 12, 15 (-3) = -45


Therefore, split 12x as 15x – 3x


Therefore,


x2 + 12x – 45 = x2 + 15x – 3x – 45


= x (x + 15) – 3 (x + 15)


= (x – 3) (x + 15)



Question 2.

Factorize each of the following algebraic expressions:



Answer:

- (x2 – 3x – 40)

In order to factorize the given expression, we find to find two numbers p and q such that:


p + q = - 3, pq = - 40


Clearly,


5 – 8 = -3, 5 (-8) = -40


Therefore, split -3x as 5x – 8x


Therefore,


x2 - 3x – 40 = x2 + 5x – 8x – 40


= x (x + 5) – 8 (x + 5)


= (x – 8) (x + 5)



Question 3.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = 3, pq = -88


Therefore, split 3a as 11a – 8a


Therefore,


a2 + 3a – 88 = a2 + 11a – 8a – 88


= a (a + 11) – 8 (a + 11)


= (x – 8) (a + 11)



Question 4.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = -14, pq = -51


Clearly,


3 – 17 = -14, 3 (-17) = -51


Therefore, split 14a as 3a – 17a


Therefore,


a2 – 14a – 51 = a2 + 3a – 17a – 51


= a (a + 3) – 17 (a + 3)


= (a – 17) (a + 3)



Question 5.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = 14, pq = 45


Clearly,


5 + 9 = 14, 5 (9) = 45


Therefore, split 14x as 5x + 9x


Therefore,


x2 + 14x + 45 = x2 + 5x + 9x + 45


= x (x + 5) – 9 (x + 5)


= (x + 9) (x + 5)



Question 6.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = -22, pq = 120


Clearly,


-12 – 10 = -22, (-12) (-10) = -120


Therefore, split -22x as -12x – 10x


Therefore,


x2 - 22x + 120 = x2 - 12x – 10x + 120


= x (x - 12) – 10 (x - 12)


= (x – 10) (x - 12)



Question 7.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = -11, pq = -42


Clearly,


3 – 14 = -11, 3 (-14) = -42


Therefore, split (-11x) as 3x – 14x


Therefore,


x2 - 11x – 42 = x2 + 3x – 14x – 42


= x (x + 3) – 14 (x + 3)


= (x – 14) (x + 3)



Question 8.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = 2, pq = -3


Clearly,


p = 3, q = -1


Therefore, split (2a) as (3a – a)


Therefore,


a2 + 2a – 3 = a2 + 3a – a – 3


= a (a + 3) – 1 (a + 3)


= (a – 1) (a + 3)



Question 9.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = 14, pq = 48


Clearly,


8 + 6 = 14, 8 (6) = 48


Therefore, split (14a) as 8a + 6a


Therefore,


a2 + 14a + 48 = a2 + 8a + 6a + 48


= a (a + 8) + 6 (a + 8)


= (a + 6) (a + 8)



Question 10.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = -4, pq = -21


Clearly,


3 – 7 = -4, 3 (-7) = -21


Therefore, split (-4x) as 3x – 7x


Therefore,


x2 + 4x – 21 = x2 + 3x – 7x – 21


= x (x + 3) – 7 (x + 3)


= (x – 7) (x + 3)



Question 11.

Factorize each of the following algebraic expressions:



Answer:

In order to factorize the given expression, we find to find two numbers p and q such that:

p + q = 5, pq = -36


Clearly,


9 – 4 = 5, 9 (-4) = -36


Therefore, split 5y as 9y – 4y


Therefore,


y2 + 5y – 36 = y2 + 9y – 4y – 36


= y (y + 9) – 4 (y + 9)


= (y – 4) (y + 9)



Question 12.

Factorize each of the following algebraic expressions:



Answer:

It can be written as (a2 – 5a)2 - 62

Using a2 – b2 = (a + b) (a – b)


(a2 – 5a)2 – 62 = (a2 – 5a + 6) (a2 – 5a – 6)


To factorize (a2 – 5a + 6), we need to find p and q where,


p + q = -5, pq = 6


Clearly,


-2 – 3 = -5, (-2) (-3) = 6


Therefore, split -5a as a – 6a


Therefore,


a2 -5a – 6 = a2 - a – 6a + 6


= (a – 6) (a – 1)


Therefore,


(a2 – 5a)2 – 3b = (a2 – 5a + b) (a2 – 5a – 6)


= (a – 1) (a – 2) (a – 3) (a – 6)



Question 13.

Factorize each of the following algebraic expressions:



Answer:

a2 – 3a – 54

In order to factorize the given expression, we find to find two numbers p and q such that:


p + q = -3, pq = -54


Clearly,


6 – 9 = - 3, 6 (-9) = -54


Therefore, split – 3a as 6a – 9a


Therefore,


a2 – 3a – 54 = a2 + 6a – 9a – 54


= (a - 9) (a + 6)


Therefore,


(a + 7) (a – 10) + 16 = (a – 9) (a + 6)




Exercise 7.8
Question 1.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 2, coefficient of x = 5and constant term = 3

We shall now split up the coefficient of x i.e., 5 into two parts whose sum is 5 and product is 2 * 3 = 6


So, we write middle term 5x as 2x + 3x


Thus, we have


2x2 + 5x + 3 = 2x2 + 2x + 3x + 3


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


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



Question 2.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 2, coefficient of x = - 3 and constant term = -2

We shall now split up the coefficient of x i.e., -3 into two parts whose sum is -3 and product is 2 * -2 = - 4


So, we write middle term -3x as -4x + x


Thus, we have


2x2 - 3x – 2 = 2x2 - 4x + x – 2


= 2x (x – 2) + 1 (x – 2)


= (x – 2) (2x + 1)



Question 3.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 3, coefficient of x = 10 and constant term = 3

We shall now split up the coefficient of x i.e., 10 into two parts whose sum is 10 and product is 3 * 3 = 9


So, we write middle term 10x as 9x + x


Thus, we have


3x2 + 10x + 3 = 3x2 + 9x + x + 3


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


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



Question 4.

Resolve each of the following quadratic trinomials into factors:



Answer:

= - 2x2 + 7x – 6

Here, coefficient of x2 = -2, coefficient of x = 7and constant term = -6


We shall now split up the coefficient of x i.e., 7 into two parts whose sum is 7 and product is -2 * -6 = 12


Clearly,


4 + 3 = 7 and,


4 * 3 = 12


So, we write middle term 7x as 4x + 3x


Thus, we have


-2x2 + 7x – 6 = -2x2 + 4x + 3x – 6


= -2x (x – 2) + 3 (x – 2)


= (x – 2) (3 – 2x)



Question 5.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 7, coefficient of x = -19 and constant term = -6

We shall now split up the coefficient of x i.e., -19 into two parts whose sum is -19 and product is 7 * -6 = -42


Clearly,


2 - 21 = -19 and,


2 * (-21) = - 42


So, we write middle term - 19x as 2x - 21x


Thus, we have


7x2 - 19x – 6 = 7x2 + 2x - 21x – 6


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


= (7x + 2) (x – 3)



Question 6.

Resolve each of the following quadratic trinomials into factors:



Answer:

28 – 31x – 5x2 = - 5x2 – 31x + 28

Here, coefficient of x2 = -5, coefficient of x = - 31 and constant term = 28


We shall now split up the coefficient of x i.e., - 31 into two parts whose sum is - 31 and product is -5 (28) = - 140


Clearly,


4 - 35 = - 31 and,


4 (-35) = - 140


So, we write middle term - 31x as 4x - 35x


Thus, we have


– 5x2 – 31x + 28 = -5x2 + 4x - 35x + 28


= -x (5x – 4) - 7 (5x – 4)


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



Question 7.

Resolve each of the following quadratic trinomials into factors:



Answer:

3 + 23y – 8y2 = - 8y2 + 23y + 3

Here, coefficient of y2 = -8, coefficient of y = 23 and constant term = 3


We shall now split up the coefficient of x i.e., 23 into two parts whose sum is 23 and product is -8 (3) = - 24


Clearly,


24 - 1 = 23 and,


24 (-1) = - 24


So, we write middle term 23y as 24y - y


Thus, we have


-8y2 + 23y + 3 = - 82 + 24y - y + 3


= -8y (y – 3) - 1 (y – 3)


= - (8y + 1) (y – 3)



Question 8.

Resolve each of the following quadratic trinomials into factors:



Answer:

11x2 – 54x + 63

Here, coefficient of x2 = 11, coefficient of x = - 54 and constant term = 63


We shall now split up the coefficient of x i.e., -54 into two parts whose sum is - 54 and product is 11 * 63 = 693


Clearly,


-33x - 21x = - 54x and,


(-33) * (-21) = 693


So, we write middle term - 54x as - 33x - 21x


Thus, we have


11x2 – 54x + 63 = 11x2 - 33x - 21x – 6


= 11x (x – 3) - 21 (x – 3)


= (11x – 21) (x – 3)



Question 9.

Resolve each of the following quadratic trinomials into factors:



Answer:

7x – 6x2 + 20 = - 6x2 + 7x + 20

Here, coefficient of x2 = -6, coefficient of x = 7and constant term = 20


We shall now split up the coefficient of x i.e., 7 into two parts whose sum is 7 and product is -6 * 20 = - 120


Clearly,


15 - 8 = 7 and,


15 (-8) = - 120


So, we write middle term 7x as 15x - 8x


Thus, we have


-6x2 + 7x + 20 = -6x2 + 15x - 8x + 20


= -3x (2x – 5) - 4 (2x – 5)


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



Question 10.

Resolve each of the following quadratic trinomials into factors:



Answer:

3x2 + 22x + 35

Here, coefficient of x2 = 3, coefficient of x = 22 and constant term = 35


We shall now split up the coefficient of x i.e., 22 into two parts whose sum is 22 and product is 3 * 35 = 105


So, we write middle term 22x as 15x + 7x


Thus, we have


3x2 + 22x + 35= 3x2 + 15x + 7x + 35


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


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



Question 11.

Resolve each of the following quadratic trinomials into factors:



Answer:

12x2 – 17xy + 6y2

Here, coefficient of x2 = 12, coefficient of x = -17and constant term = 6y2


We shall now split up the coefficient of middle term i.e., -17y into two parts whose sum is -17y and product is 12 * 6y2 = 72y2


Clearly,


-9y – 8y = -17y and,


(-9y) (-8y) = 72y2


So, we replace middle term -17xy = - 9xy – 8xy


Thus, we have


12x2 -17xy+ 6y2 = 12x2 - 9xy - 8xy + 6y2


= 3x (4x – 3y) – 2y (4x – 3y)


= (3x – 2y) (4x – 3y)



Question 12.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 6, coefficient of x = -5y and constant term = - 6y2

We shall now split up the coefficient of middle term i.e., -5y into two parts whose sum is -5y and product is 6 (-6y2) = - 36y2


Clearly,


4y – 9y = -5y and,


(4y) (-9y) = - 36y2


So, we replace middle term -5xy = 4xy – 9xy


Thus, we have


6x2 -5xy- 6y2 = 6x2 + 4xy - 9xy - 6y2


= (2x – 3y) (3x + 2y)



Question 13.

Resolve each of the following quadratic trinomials into factors:

6x2 – 13xy + 2y2


Answer:

Here, coefficient of x2 = 6, coefficient of x = -13y and constant term = 2y2

We shall now split up the coefficient of middle term i.e., -13y into two parts whose sum is -13y and product is 6 (2y2) = 12y2


Clearly,


-12y – y = -13y and,


(-12y) (-y) = 12y2


So, we replace middle term -13xy = -12xy – xy


Thus, we have


6x2 -13xy+ 2y2 = 6x2 - 12xy - xy - 2y2


= (6x – y) (x - 2y)



Question 14.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 14, coefficient of x = 11y and constant term = - 15y2

We shall now split up the coefficient of middle term i.e., 11y into two parts whose sum is 11y and product is 14 (-15y2) = - 210y2


Clearly,


21y – 10y = 11y and,


(21y) (-10y) = - 210y2


So, we replace middle term 11xy = 21xy – 10xy


Thus, we have


14x2 + 11xy- 15y2 = 14x2 + 21xy - 10xy - 15y2


= 2x (7x – 5y) + 3y (7x – 5y)


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



Question 15.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of a2 = 6, coefficient of a = 17b and constant term = - 3b2

We shall now split up the coefficient of middle term i.e., 17b into two parts whose sum is 17b and product is 6 (-3b2) = - 18b2


Clearly,


18b – b = 17b and,


6 (-3b2) = - 36y2


So, we replace middle term 17ab = 18ab – ab


Thus, we have


6a2 +17ab– 3b2 = 6a2 + 18ab - ab – 3b2


= 6a (a + 3b) – b (a + 3b)


= (6a – b) (a + 3b)



Question 16.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of a2 = 36, coefficient of a = 12bc and constant term = - 15b2c2

We shall now split up the coefficient of middle term i.e., 12bc into two parts whose sum is 12bc and product is 36 (-15b2c2) = - 500b2c2


So, we replace middle term 12abc = 30abc – 18abc


Thus, we have


36a2 –12abc– 15b2c2 = 36a2 + 30abc – 18abc – 15b2c2


= (6a + 5bc) (6a – 3bc)



Question 17.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of x2 = 15, coefficient of x = -16yz and constant term = - 15y2z2

We shall now split up the coefficient of middle term i.e., -16yz into two parts whose sum is -16yz and product is 15 (-15y2z2) = - 225y2z2


Clearly,


-25yz + 9yz = -16yz and,


(-25yz) (9yz) = - 225y2z2


So, we replace middle term -16xyz = -25yz – 9yz


Thus, we have


15x2 -16xyz- 15y2z2 = 15x2 - 25yz + 9yz - 15y2z2


= 5x (3x – 5yz) + 3yz (3x – 5yz)


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



Question 18.

Resolve each of the following quadratic trinomials into factors:



Answer:

x2 + 4y2 – 4xy – 5x + 10y + 6

Here, coefficient of (x – 2y)2 = 1, coefficient of (x – 2y ) = -5 and constant = 6


We shall now split up the coefficient of middle term i.e., -5 into two parts whose sum is -5 and product is 6 (1) = 6


Clearly,


-2 - 3 = -5 and,


-2 (-3) = 6


So, we replace-5 (x – 3y) = -2 (x – 2y) – 3 (x – 2y)


Thus, we have


(x – 2y)2 – 5 (x – 2y) + 6 = (x – 2y)2 – 2 (x – 2y) – 3 (x – 2y) + 6


= (x – 2y - 2) (x - 2y - 3)



Question 19.

Resolve each of the following quadratic trinomials into factors:



Answer:

Here, coefficient of (2a – b)2 = 1, coefficient of (2a – b) = 2 and constant term = - 8

We shall now split up the coefficient of middle term i.e., 2 into two parts whose sum is 2 and product is -8 (1) = - 8


Clearly,


4 - 2 = 2 and,


4 (-2) = - 8


So, we replace 2 (2a – b) = 4 (2a –b) – 2 (2a – b)


Thus, we have


(2a – b)2 + 2 (2a – b) – 8 = (2a – b)2 + 4 (2a – b) – 2 (2a – b) - 8


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


= (2a – b – 2) (2a – b + 4)




Exercise 7.9
Question 1.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

p2 + 6p + 8

Here, coefficient of p2 is unity so we add and subtract square of half of coefficient of p


Therefore,


p2 + 6p + 8 = p2 + 6p + 32 – 32 + 8 (Adding and subtracting 32)


= (p + 3)2 – 12 (By completing the square)


= (p + 3 – 1) (p + 3 + 1)


= (p + 2) (p + 4)



Question 2.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

q2 – 10q + 21 Coefficient of q2 is 1 so we add and subtract square of half of coefficient of q

Therefore,


q2 – 10q + 21 = q2 – 10q+ 52 – 52 + 21 (Adding and subtracting 52)


= (q – 5)2 – 22 (By completing the square)


= (q – 5 – 2) (q – 5 + 2)


= (q – 7) (q – 3)



Question 3.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

4y2 + 12y + 5

We have 4y2 + 12y + 5 = 4 (y2 + 3y + ) [Therefore, coefficient of y2 = 1]


= 4 [y2 + 3y + ()2 – ()2 + ]


= 4 [(y + )2 – 12] (Completing the square)


= 4 (y + + 1) (y + – 1)


= (2y + 5) (2y + 1)



Question 4.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

p2 + 6p – 16

Coefficient of p2 = 1


Therefore, we have


p2 + 6p + 32 – 32 – 16 (Adding and subtracting 32)


= (p + 3)2 – 52 (Completing the square)


= (p + 3 + 5) (p + 3 – 5)


= (p + 8) (p – 2)



Question 5.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

x2 + 12x + 20

Coefficient of x2 = 1


Therefore, we have


x2 + 12x + 62 – 62 + 20 (Adding and subtracting 62)


= (x + 6)2 – 42 (Completing the square)


= (x + 6 + 4) (x + 6 – 4)


= (x + 10) (x + 2)


= 4 [x - + 1] [x - – 1]


= (2x – 1) (2x – 5)



Question 6.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

a2 – 14a – 51

Coefficient of a2 = 1


Therefore, we have


a2 – 14a – 51 = a2 – 14a + 72 – 72 – 51 (Therefore, adding and subtracting 72)


= (a – 7)2 – 102 (Completing the square)


= (a – 7 + 10) (9 – 7 – 10)


= (a + 3) (a – 17)



Question 7.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

a2 + 2a – 3

Coefficient of a2 = 1


Therefore, we have


a2 + 2a – 3 = a2 + 2a + 12 – 12 – 3 (Adding and subtracting 12)


= (a + 1)2 – 22 (Completing the square)


= (a + 1 + 2) (a + 1 – 2)


= (a + 3) (a – 1)



Question 8.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

4x2 – 12x + 5

We have,


4x2 – 12x + 5 = 4 (x2 – 3x + )


= 4 [x2 – 3x + ()2 – ()2 + )] [Therefore, adding and subtracting ()2]


= 4 [(x - )2 – 12] (Therefore, completing the square)



Question 9.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

y2 – 7y + 12

Coefficient of y2 = 1


Therefore, we have


y2 – 7y + 12 = y2 – 7y + ()2 – ()2 + 12 [By adding and subtracting ()2]


= (y - )2 – ()2 (Completing the square)


= (y - - ) (y - + )


= (y – 4) (y – 3)



Question 10.

Factorize each of the following quadratic polynomials by using the method of completing;



Answer:

z2 – 4z – 12

Coefficient of z2 = 1


Therefore, we have


z2 – 4z – 12 = z2 – 4z + 22 – 22 – 12 [By adding and subtracting 22]


= (z – 2)2 – 42 (Completing the square)


= (z – 2 + 4) (z – 2 – 4)


= (z + 2) (z – 6)