Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
x2 + 7x + 12
Let f(x) = x2 + 7x + 12
Put f(x) = 0
x2 + 7x + 12 = 0
x2 + 4x + 3x + 12 = 0
3(x + 4) + x(x + 4) = 0
(3 + x) (x + 4) = 0
∴ x = -4 or x = -3
Now,
sum of zeroes = -3 + (-4) = -7=
Product of zeroes = (-3) × (-4)
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
x2 + 2x – 8
Let f(x) = x2 + 2x - 8
Put f(x) = 0
x2 + 2x - 8 = 0
x2 + 2x - 4x - 8 = 0
x(x + 2) – 4 (x + 2) = 0
(2 + x) (x - 4) = 0
∴ x = 4 or x = -2
Now, sum of zeroes = -2 + 4 = 2 =
Product of zeroes = (4) × (-2)
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
x2 + 3x – 10
Let f(x) = x2 + 3x - 10
Put f(x) = 0
x2 + 3x - 10 = 0
x2 + 5x - 2x - 10 = 0
x(x + 5) - 2(x + 5) = 0
(5 + x) (x - 2) = 0
∴ x = -5 or x = 2
Now, sum of zeroes = -5 + (2) = -3 =
Product of zeroes = (-5) × (2)
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
4x2 – 4x – 3
Let f(x) = 4x2 - 4x - 3
Put f(x) = 0
4x2 - 4x - 3 = 0
4x2 - 6x + 2x - 3 = 0
2x(2x - 3) + 1(2x - 3) = 0
(2x + 1) (2x - 3) = 0
Now, sum of zeroes = 1 =
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
5x2 – 4 – 8x
Let f(x) = 5x2 - 4 – 8x
Put f(x) = 0
5x2 - 8x - 4 = 0
5x2 - 10x + 2x - 4 = 0
5x(x - 2) + 2(x - 2) = 0
(5x + 2) (x - 2) = 0
Now, sum of zeroes == =
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
Let f(x)= 2√3 x2 - 5x + √3
Put f(x) = 0
Now,
sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
2x2 – 11x + 15
Let f(x) = 2x2 – 11x + 15
Put f(x) = 0
2x2 - 11x + 15 = 0
2x2 - 6x - 5x + 15 = 0
2x(x - 3) - 5(x - 3) = 0
(2x - 5) (x - 3) = 0
Now, sum of zeroes= =
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
4x2 – 4x + 1
Let f(x) =4x2 – 4x + 1 8x
Put f(x) = 0
4x2 - 4x + 1 = 0
(2x)2 – 2(2x)(1) + (1)2 = 0
(2x - 1)2 = 0
Now,
sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
x2 – 5
Let f(x) = x2 – 5
Put f(x) = 0
x2 – 5 = 0
(x – √5) (x + √5) = 0
∴ x = √5 or x = -√5
Now, sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
8x2 – 4
Let f(x) = 8x2 – 4
Put f(x) = 0
8x2 – 4 = 0
(2√2x – 2) (2√2x + 2) = 0
Now, sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
5y2 + 10y
Let f(x) = 5y2 + 10y
Put f(x) = 0
5y2 + 10y = 0
(5y) (y + 2) = 0
∴ x =0 or x = -2
Now, sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the zeros of the following quadratic polynomials and verify the relationship between the zeros and the coefficients:
3x2 – x – 4
Let f(x) =3x2 – x – 4
Put f(x) = 0
3x2 - x – 4 = 0
3x2 - 4x + 3x - 4 = 0
x(3x - 4) + 1(3x - 4) = 0
(x + 1) (3x - 4) = 0
Now, sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the quadratic polynomial whose zeros are 2 and ‒6. Verify the relation between the coefficients and the zeros of the polynomial.
Let α = 2 and β = -6
Now, Sum of zeros, α + β = 2 – 6 = -4
And, product of zeroes, αβ = 2(-6) = -12
We know that,
Required polynomial = x2–(α + β) x + αβ
= x2–(- 4)x + (-12)
= x2 + 4x – 12
Now, sum of zeroes =
Product of zeroes =
Hence, relationship verified.
Find the quadratic polynomial whose zeros are . Verify the relation between the coefficients and the zeros of the polynomial.
Now, Sum of zeros,
And, product of zeroes,
We know that,
Required polynomial = x2–(α + β)x + αβ
=12x2 – 5x – 2
Now, sum of zeroes
Product of zeroes
Hence, relationship verified.
Find the quadratic polynomial, sum of whose zeros is 8 and their product is 12. Hence, find the zeros of the polynomial
Let the zero of the polynomial be α and β
According to the question,
α + β = 8
αβ = 12
∴f(x)= x2 – (α + β)x + (αβ)
=x2 - 8x + 12
∴required polynomial f(x) = x2 - 8x + 12
Put f(x) = 0
x2 - 8x + 12 = 0
x2 - 6x -2x + 12 = 0
x(x – 6) -2(x – 6) = 0
(x - 6)(x - 2)=0
x = 6 or x = 2
Find the quadratic polynomial, the sum of whose zeros is 0 and their product is ‒1. Hence, find the zeros of the polynomial.
Let the zero of the polynomial be α and β
According to the question,
α + β = 0
αβ = -1
∴f(x)= x2 – (α + β)x + (αβ)
=x2 - 0x - 1
∴required polynomial f(x) = x2 - 1
Put f(x) = 0
x2 - 1 = 0
(x - 1)(x + 1)=0
x = 1 or x = -1
Find the quadratic polynomial, the sum of whose zeros is and their product is 1. Hence, find the zeros of the polynomial.
Let the zero of the polynomial be α and β
According to the question:
Sum of zeroes:αβ = 1
we know,∴f(x)= x2 – (α + β)x + (αβ)
∴ required polynomial f(x)
Put f(x) = 0
x2 –(5/2)x + 1= 0
2x2 – 5x + 2 = 0
2x2 – 4x – x + 2 = 0
2x(x – 2) – 1(x - 2) =0
(x - 2)(2x - 1) = 0
x = 2 or x = 1/2
Find the quadratic polynomial, the sum of whose roots is √2 and their product is 1/3.
Let the zero of the polynomial be α and β
According to the question,
α + β = √2
∴ f(x)= x2 – (α + β)x + (αβ)
∴ required polynomial f(x)= x2 - √2 x + 1/3
Put f(x) = 0
x2 - √2 x + 1/3 = 0
3x2 – 3√2x + 1 = 0
If and x = ‒3 are the roots of the quadratic equation ax2 + 7x + b = 0 then find the values of a and b.
We have, ax2 + 7x + b = 0
Now, Sum of zeros
∴a = 3 (i)
Product of zeroes (From i)
∴b= -6
If (x + a) is a factor of the polynomial 2x2 + 2ax + 5x + 10, find the value of a.
Since, x + a is a factor of 2x2 + 2ax + 5x + 10
∴ x + a = 0
x = -a
Put x = -a in 2x2 + 2ax + 5x + 10 = 0
2(-a)2 + 2a(-a) + 5(-a) + 10 = 0
2a2 – 2a2 – 5a + 10 = 0
-5a = - 10
a = 2
One zero of the polynomial 3x3 + 16x2 + 15x – 18 is 2/3. Find the other zeros of the polynomial.
It is given in the question that,
x = 2/3 is one of the zeros of the given polynomial 3x3 + 16x2 + 15x – 18
We have, x = 2/3
x –2/3 = 0
To find the quotient we have to divide the given polynomial by x – 2/3
Quotient = 3x2 + 18x + 27
∴ 3x2 + 18x + 27 = 0
3x2 + 9x + 9x + 27 = 0
3x (x + 3) + 9 (x + 3) = 0
(x + 3) (3x + 9) = 0
(x + 3) = 0 or (3x + 9) = 0
Hence, x = - 3 or x = - 3
Verify that 3, ‒2, 1 are the zeros of the cubic polynomial p(x) = x3 – 2x2 – 5x + 6 and verify the relation between its zeros and coefficients.
It is given in the question that,
p (x) = x3 – 2x2 – 5x + 6
Also, 3, -2 and 1 are the zeros of the given polynomial
∴ p (3) = (3)3 – 2 (3)2 – 5 (3) + 6
= 27 – 18 – 15 + 6
= 33 – 33
= 0
p (-2) = (-2)3 – 2 (-2)2 – 5 (-2) + 6
= -8 – 8 + 10 + 6
= - 16 + 16
= 0
And, p (1) = (1)3 – 2 (1)2 – 5 (1) + 6
= 1 – 2 – 5 + 6
= 7 – 7
= 0
Verification of the relation is as follows:
Let us assume = 3, = - 2 and = 1
= 3 – 2 + 1
= 2
∴
Also, + + = 3 (-2) + (-2) (1) + 1 (3)
= - 6 – 2 + 3
= - 5
∴
And, = 3 × (-2) × 1
= - 6
∴
Verify that 5, –2 and are the zeros of the cubic polynomial p(x) = 3x3 - 10x2– 27x + 10 and verify the relation between its zeros and coefficients
It is given in the question that,
p (x) = 3x3 – 10x2 – 27x + 10
Also, 5, -2 and are the zeros of the given polynomial
∴ p (5) = 3 (5)3 – 10 (5)2 – 27 (5) + 10
= 3 × 125 – 250 – 135 + 10
= 385 – 385
= 0
p (-2) = 3 (-2)3 – 10 (-2)2 – 27 (-2) + 10
= - 24 – 40 + 54 + 10
= - 64 + 64
= 0
And, p () = 3 ()3 – 10 ()2 – 21 () + 10
=
=
= 0
Verification of the relation is as follows:
Let us assume α = 5, β = - 2 and γ = 1/3
α + β + γ = 5 – 2 + 1/3 =
∴
Also, + + = 5 (-2) + (-2) () + () (5)
= - 27/3
= - 9
∴
And, αβγ =
Hence, verified
Find a cubic polynomial whose zeros are 2, –3 and 4
Let the zeros of the polynomial be a, b and c
Where a = 2, b = - 3 and c = 4
The cubic polynomial can be calculated as follows:
x3 – (a + b + c) x2 + (ab + bc + ca)x – abc
Putting the values of a, b and c in the above equation we get:
= x3 – (2 – 3 + 4) x2 + (-6 – 12 + 8) x – (- 24)
= x3 – 3x2 – 10x + 24
Find a cubic polynomial whose zeros are , 1 and –3.
Let the zeros of the polynomial be a, b and c
Where a = 1/2, b = 1 and c = - 3
The cubic polynomial can be calculated as follows:
x3 – (a + b + c) x2 + (ab + bc + ca) x – abc
Putting the values of a, b and c in the above equation we get:
= x3 – (1/2 + 1 - 3) x2 + (1/2 – 3 – 3/2)x – (- 3/2)
= x3 – (-3/2) x2 – 4x + 3/2
= 2x3 + 3x2 – 8x + 3
Find a cubic polynomial with the sum, sum of the product of its zeros taken two at a time, and the product of its zeros as 5, –2 and –24 respectively.
The required cubic polynomial can be calculated as:
x3 – (Sum of the zeros) x2 + (Sum of the product of the zeros taking two at a time) x – Product of Zeros
It is given that, sum of the product of its zeros taken two at a time, and the product of its zeros as 5, –2 and –24 respectively
Putting these values in the equation, we get:
x3 – 5x2 – 2x + 24
Find the quotient and the remainder when:
f(x) = x3 – 3x2 + 5x –3 is divided by g(x) = x2 – 2.
It is given in the question that,
f (x) = x3 – 3x2 + 5x – 3
And, g (x) = x2 – 2
Hence,
Quotient q (x) = x – 3
Remainder r (x) = 7x – 9
Find the quotient and the remainder when:
f(x) = x4 – 3x2 + 4x + 5 is divided by g(x) = x2 + 1 – x.
It is given in the question that,
f (x) = x4 – 3x2 + 4x + 5
And, g (x) = x2 + 1 – x
Hence,
Quotient q (x) = x2 + x - 3
Remainder r (x) = 8
Find the quotient and the remainder when:
f(x) = x4 – 5x + 6 is divided by g(x) = 2 – x2.
It is given in the question that,
f (x) = x4 – 5x + 6 = x4 + 0x3 + 0x2 – 5x + 6
And, g (x) = x2 + 1 – x
Hence,
Quotient q (x) = x2 – 2
Remainder r (x) = 5x + 10
By actual division, show that x3 – 3 is a factor 2x4 + 3x3 – 2x2 – 9x – 12.
It is given in the question that,
f (x) = 2x4 + 3x3 – 2x2 – 9x – 12
And, g (x) = x3 – 3
Hence,
Quotient q (x) = 2x2 + 3x + 4
Remainder r (x) = 0
As the remainder is 0
∴ x2 – 3 is a factor of 2x4 + 3x3 – 2x2 – 9x – 12
On dividing 3x3 + x2 + 2x + 5 by a polynomial g(X), the quotient and remainder are (3x – 5) and (9x + 10) respectively. Find g(x).
We know that,
According to the division rule, we have
Dividend = Quotient × Divisor + Remainder
Here, we have:
Dividend = 3x3 + x2 + 2x + 5
Quotient = 3x – 5
Remainder = 9x + 10
Putting these values in the formula, we get
3x3 + x2 + 2x + 5 = 3x – 5 × g (x) + 9x + 10
3x3 + x2 + 2x + 5 – 9x – 10 = (3x – 5) × g(x)
3x3 + x2 – 7x – 5 = (3x – 5) × g (x)
g (x) =
∴ g (x) = x2 + 2x + 1
Verify division algorithm for the polynomials f(x) = 8 + 20x + x2 ‒ 6x3 and g(x) = 2 + 5x ‒ 3x2.
It is given in the question that,
f (x) = - 6x3 + x2 + 20x + 8
g (x) = - 3x2 + 5x + 2
∴ Quotient = 2x + 3
Remainder = x + 2
We know that, according to division rule:
Dividend = Quotient × Divisor + Remainder
Putting the values in the above formula, we get:
- 6x3 + x2 + 20x + 8 = (- 3x2 + 5x + 2) (2x + 3) + (x + 2)
-6x3 + x2 + 20x + 8 = - 6x3 + 10x2 + 4x – 9x2 + 15x + 6 + x + 2
-6x3 + x2 + 20x + 8 = -6x3 + x2 + 20x + 8
It is given that ‒1 is one of the zeros of the polynomial x3 + 2x2 ‒ 11x ‒ 12. Find all the zeros of the given polynomial.
Let us assume f (x) = x3 + 2x2 ‒ 11x ‒ 12
It is given in the question that, -1 is a zero of the polynomial
∴ (x + 1) is a factor of f (x)
Now on dividing f (x) by (x + 1), we get
f (x) = x3 + 2x2 ‒ 11x ‒ 12
= (x + 1) (x2 + x – 12)
= (x + 1) {x2 + 4x – 3x – 12}
= (x + 1) {x (x + 4) – 3 (x + 4)}
= (x + 1) (x – 3) (x + 4)
∴ f (x) = 0
(x + 1) (x – 3) (x + 4) = 0
(x + 1) = 0 0r (x – 3) = 0 or (x + 4) = 0
x = -1 or x = 3 or x = - 4
Hence, zeros of the polynomial are -1, 3 and -4
If 1 and ‒2 are two zeros of the polynomial (x3 ‒ 4x2 ‒ 7x + 10), find its third zero.
Let us assume f (x) = x3 – 4x2 – 7x + 10
As 1 and – 2 are the zeros of the given polynomial therefore each one of (x – 1) and (x + 2) is a factor of f (x)
Consequently, (x – 1) (x + 2) = (x2 + x – 2) is a factor of f (x)
Now, on dividing f (x) by (x2 + x – 2) we get:
f (x) = 0
(x2 + x – 2) (x – 5) = 0
(x – 1) (x + 2) (x – 5) = 0
∴ x = 1 or x = - 2 or x = 5
Hence, the third zero is 5
If 3 and ‒3 are two zeros of the polynomial (x4 + x3 ‒ 11x2 ‒ 9x + 18), find all the zeros of the given polynomial.
Let us assume f (x) = x4 + x3 ‒ 11x2 ‒ 9x + 18
As 3 and – 3 are the zeros of the given polynomial therefore each one of (x + 3) and (x - 3) is a factor of f (x)
Consequently, (x – 3) (x + 3) = (x2 – 9) is a factor of f (x)
Now, on dividing f (x) by (x2 – 9) we get:
f (x) = 0
(x2 + x – 2) (x2 – 9) = 0
(x – 1) (x + 2) (x – 3) (x + 3) = 0
∴ x = 1 or x = - 2 or x = 3 or x = - 3
Hence, all the zeros of the given polynomial are 1, -2, 3 and -3
If 2 and ‒2 are two zeros of the polynomial (X4 + x3 ‒ 34x2 ‒ 4x + 120), find all the zeros of the given polynomial.
Let us assume f (x) = x4 + x3 ‒ 34x2 ‒ 4x + 120
As 2 and – 2 are the zeros of the given polynomial therefore each one of (x - 2) and (x + 2) is a factor of f (x)
Consequently, (x – 2) (x + 2) = (x2 – 4) is a factor of f (x)
Now, on dividing f (x) by (x2 – 4) we get:
f (x) = 0
(x2 + x – 30) (x2 – 4) = 0
(x2 + 6x – 5x – 30) (x – 2) (x + 2)
[x (x + 6) – 5 (x + 6)] (x – 2) (x + 2)
(x – 5) (x + 6) (x – 2) (x + 2) = 0
∴ x = 5 or x = - 6 or x = 2 or x = - 2
Hence, all the zeros of the given polynomial are 2, -2, 5 and -6
Find all the zeros of (x4 + x3 ‒ 23x2 ‒ 3x + 60), if it is given that two of its zeros are √3 and ‒√3.
Let us assume f (x) = x4 + x3 ‒ 23x2 ‒ 3x + 60
As √3 and –√3 are the zeros of the given polynomial therefore each one of (x - √3) and (x - √3) is a factor of f (x)
Consequently, (x – √3) (x + √3) = (x2 – 3) is a factor of f(x)
Now, on dividing f (x) by (x2 – 3) we get:
f (x) = 0
(x2 + x – 20) (x2 – 3) = 0
(x2 + 5x – 4x – 20) (x2 – 3)
[x (x + 5) – 4 (x + 5)] (x2 – 3)
(x – 4) (x + 5) (x – ) (x + ) = 0
∴ x = 4 or x = - 5 or x = or x = -
Hence, all the zeros of the given polynomial are , -, 4 and - 5
Find all the zeros of (2x4 ‒ 3x3 ‒ 5x2 + 9x ‒ 3), it being given that two of its zeros are √3 and – √3.
Let us assume f (x) = 2x4 - 3x3 ‒ 5x2 + 9x - 3
As and – are the zeros of the given polynomial therefore each one of (x - ) and (x + ) is a factor of f (x)
Consequently, (x – ) (x + ) = (x2 – 3) is a factor of f (x)
Now, on dividing f (x) by (x2 – 3) we get:
f (x) = 0
2x2 - 3x2 – 5x2 + 9x - 3 = 0
(x2 – 3) (2x2 – 3x + 1) = 0
(x2 - 3) (2x2 – 2x – x + 1) (2x – 1) (x - 1) = 0
(x – ) (x + ) (2x – 1) (x - 1) = 0
∴ x = or x = - or x = or x = 1
Hence, all the zeros of the given polynomial are , -, and 1
Obtain all other zeros of (x4 + 4x3 ‒ 2x2 ‒ 20x ‒15) if two of its zeros are √5 and – √5.
Let us assume f (x) = x4 + 4x3 ‒ 2x2 ‒ 20x - 15
As (x-√5) and (x-√5) are the zeros of the given polynomial therefore each one of (x-√5) and (x + √5) is a factor of f (x)
Consequently, (x-√5) (x + √5) = (x2 – 5) is a factor of f (x)
Now, on dividing f (x) by (x2 – 5) we get:
f (x) = 0
x4 + 4x3 – 7x2 – 20x – 15 = 0
(x2 – 5) (x2 + 4x + 3) = 0
(x -√5) (x + √5) (x + 1) (x + 3) = 0
∴ x = √5 or x = - √5 or x = - 1 or x = - 3
Hence, all the zeros of the given polynomial are √5, -√5, - 1 and - 3
Find all the zeros of the polynomial (2x4 ‒ 11x3 + 7x2 + 13x ‒ 7), it being given that two of its zeros are (3 + √3) and (3 ‒ √3)
Let us assume f (x) = 2x4 – 11x3 + 7x2 + 13x - 7
As (3 + √2) and (3- √2) are the zeros of the given polynomial therefore each one of (x + 3 + √2) and (x + 3 - √2) is a factor of f (x)
Consequently, [(x – (3 + √2)][(x – (3 -√2)
= [(x – 3) - √2] [(x – 3) + √2]
= [(x – 3)2 – 2] = x2 – 6x + 7 is a factor of f (x)
Now, on dividing f (x) by (x2 – 6x + 7) we get:
f (x) = 0
2x4 - 11x3 + 7x2 + 13x – 7 = 0
(x2 - 6x + 7) (2x2 + x – 1) = 0
(x + 3 + √2) (x + 3 -√2) (2x – 1) (x + 1) = 0
∴ x = - 3 - √2 or x = - 3 + √2 or x = 1/2 or x = - 1
Hence, all the zeros of the given polynomial are (-3 -√2), (-3 + √2), 1/2 and – 1
If one zero of the polynomial x2 ‒ 4x + 1 is (2 + √3), write the other zero.
It is given in the question that, zero of the polynomial x2 – 4x + 1 is (2 + )
Let the other zero of the polynomial be a
We know that,
Sum of zeros =
∴ 2 + √3 + a =
a = 2 - √3
Hence, the other zero of the given polynomial is (2 -√3)
Find the zeros of the polynomial x2 + x ‒ p (p + 1).
We have,
f (x) = x2 + x – p (p + 1)
f (x) = x2 + (p + 1 - p)x – p (p + 1)
= x2 + (p + 1) x – px – p (p + 1)
= x [x + (p + 1)] – p [x + (p + 1)]
= [x + (p + 1)] (x – p)
To find the zeroes of f(x), let f (x) = 0
[x + (p + 1)] (x – p) = 0
[x + (p + 1)] = 0 or (x – p) = 0
x = p or x = - (p + 1)
Hence, the zeros of the given polynomial are p and – (p + 1)
Find the zeros of the polynomial x2 – 3x – m (m + 3).
We have,
f (x) = x2 – 3x – m (m + 3)
Now, by adding and subtracting px, we get
f (x) = x2 - mx - 3x + mx – m (m + 3)
= x [x – (m + 3)] + m [x – (m + 3)]
= [x - (m + 3)] (x + m)
∴ f (x) = 0
[x - (m + 3)] (x + m) = 0
[x - (m + 3)] = 0 or (x + m) = 0
x = m + 3 or x = - m
Hence, the zeros of the given polynomial are - m and m + 3
Find α, β are the zeros of a polynomial such that α + β= 6 and αβ = 4 then write the polynomial.
It is given in the question that,
α + β= 6
And, αβ = 4
We know that,
If the zeros of the polynomial are then the quadratic polynomial can be found as x2 – () x + (i)
Now substituting the values in (i), we get
x2 – 6x + 4
If one zeros of the quadratic polynomial kx2 + 3x + k is 2 then find the value of k.
It is given in the question that,
One of the zero of the polynomial kx2 + 3x + k is 2
∴ It will satisfy the above polynomial
Now, we have
k (2)2 + 3 (2) + k = 0
4k + 6 + k = 0
5k + 6 = 0
5k = - 6
∴ k = -6/5
If 3 is a zero of the polynomial 2x2+ x + k, find the value of k.
It is given in the question that,
One of the zero of the polynomial 2x2 + x + k is 3
∴ It will satisfy the above polynomial
Now, we have
2 (3)2 + 3 + k = 0
21 + k = 0
k = - 21
If ‒4 is a zero of the polynomial x2 ‒ x- (2k + 2) then find the value of k.
It is given in the question that,
One of the zero of the polynomial x2 – x- (2k + 2) is - 4
∴ It will satisfy the above polynomial
Now, we have
(- 4)2 – (- 4) - (2k + 2) = 0
16 + 4 - 2k - 2 = 0
- 2k = - 18
k = 18/2
∴ k = 9
If 1 is a zero of the polynomial ax2 ‒ 3 (a ‒ 1) x ‒ 1 then find the value of a.
It is given in the question that,
One of the zero of the polynomial ax2 – 3 (a – 1) x - 1 is 1
∴ It will satisfy the above polynomial
Now, we have
a (1)2 – 3(a – 1) 1 – 1 = 0
a – 3a + 3 - 1 = 0
- 2a = - 2
∴ a = 1
If ‒2 is a zero of the polynomial 3x2 + 4x + 2k then find the value of k.
It is given in the question that,
One of the zero of the polynomial 3x2 + 4x + 2k is - 2
∴ It will satisfy the above polynomial
Now, we have
3 (- 2)2 + 4 (- 2) + 2k = 0
12 - 8 + 2k = 0
4 + 2k = 0
2k = - 4
∴ k = - 2
Write the zeros of the polynomial x2 ‒ x ‒ 6.
We have,
f (x) = x2 – x – 6
= x2 – 3x + 2x – 6
= x (x – 3) + 2 (x – 3)
= (x – 3) (x + 2)
f (x) = 0
(x – 3) (x – 2) = 0
(x – 3) = 0 or (x – 2) = 0
x = 3 or x = 2
∴ The zeros of the given polynomial are 3 and – 2
If the sum of the zeros of the quadratic polynomial kx2 ‒ 3x + 5 is 1, write the value of k.
It is given in the question that, zero of the polynomial kx2 – 3x + 5 is 1
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros =
⇒
⇒ k = 3
If the product of the zeros of the quadratic polynomial x2 ‒ 4x + k is 3 then write the value of k.
It is given in the question that, zero of the polynomial x2 – 4x + k is 3
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros =
3 = k/1
k = 3
If (x + a) is a factor of (2x2 + 2ax + 5x + 10), find the value of a.
It is given in the question that,
(x + 4) is a factor of 2x2 + 2ax + 5x + 10
Now, we have
x + a = 0
x = - a
As (x + a) is a factor of 2x2 + 2ax + 5x + 10
Thus, it will satisfy the given polynomial
∴ 2 (- a)2 + 2a (- a) + 5 (- a) + 10 = 0
- 5a + 10 = 0
a = 2
If (a ‒ b), a and (a + b) are zeros of the polynomial 2x3 ‒ 6x2 + 5x – 7, write the value of a.
It is given in the question that, zero of the polynomial 2x3 – 6x2 + 5x - 7 is (a – b), a and (a + b)
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros =
a – b + a + a + b = (- (-6))/2
3a = 3
a = 1
If x3 + x2 ‒ ax + b is divisible by (x2 ‒ x), write the values of a and b.
Firstly, equating x2 – x to 0 to find the zeros we get:
x (x – 1) = 0
x = 0 or x – 1 = 0
x = 0 or x = 1
As x3 + x2 – ax + b is divisible by x2 – x
∴ The zeros o x2 – x will satisfy x3 + x2 – ax + b
Hence, (0)3 + 02 – a (0) + b = 0
b = 0
Also,
(1)3 + 12 – a (1) + 0 = 0
∴ a = 2
If α and β are the zeros of the polynomial 2x2 + 7x + 5, write the value of α + β + αβ.
It is given in the question that, zeros of the polynomial 2x2 + 7x + 5 are
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros = and product of zeros =
= and
∴
State division algorithm for polynomials.
The Division algorithm for polynomials is as follows:
If we have two polynomials f (x) and g (x) and the degree of f (x) is greater than the degree of g (x), where g (x) 0 than there exist two unique polynomials q (x) and r (x) such that:
f (x) = g (x)× q(x) + r(x)
where r (x) – 0 or degree of r (x) < degree of g (x)
The sum of the zeros and the product of zeros of a quadratic polynomial are -1/2 and ‒3 respectively. Write the polynomial.
We know that,
We can find the quadratic polynomial if we know the sum of the roots and product of the roots by using the formula:
x2 – (Sum of the zeroes)x + Product of zeros
∴ x2 – (-1/2) x + (- 3)
∴ The required polynomial is x2 + - 3
Write the zeros of the quadratic polynomial f(X) = 6x2 ‒ 3.
We know that,
To find the zeros of the quadratic polynomial we have to equate the f (x) to 0
∴ f (x) = 0
6x2 – 3 = 0
3 (2x2 – 1) = 0
2x2 – 1 = 0
2x2 = 1
x2 = 1/2
x = � 1/√2
Hence, the zeros of the quadratic polynomial f (x) are 1/√2 and -1/√2
Write the zeros of the quadratic polynomial f(x) = 4√3x2 + 5x ‒ 2√3.
We know that,
To find the zeros of the quadratic polynomial we have to equate the f (x) to 0
∴ f (x) = 0
4√3 x2 + 5x - 2√3 = 0
4√3 x2 + 8x – 3x - 2√3 = 0
4x (√3 x + 2) - √3 (√3 x + 2) = 0
(√3 x + 2) = 0 or (4x - √3) = 0
x =- or x =
Hence, the zeros of the quadratic polynomial f (x) are - or
If α and β are the zeros of the polynomial f(x) = x2 ‒ 5x + k such that α ‒ β = 1, find the value of k.
It is given in the question that,
Zeros of the polynomial x2 – 5x + k are
Also,
α- β = 1
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros = and product of zeros =
and
α + β=5 and α β = k/1
Now solving α- β=1 and α + β = 5, we get:
= 2
these values in we get:
If α and β are the zeros of the polynomial f(x) = 6x2 + x ‒ 2, find the value of
It is given in the question that,
Zeros of the polynomial 6x2 + x - 2 are
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros = and product of zeros =
= and
Now we have:
=
=
=
=
=
If α and β are the zeros of the polynomial f(x) = 5x2 ‒ 7x + 1, find the value of
It is given in the question that,
Zeros of the polynomial 5x2 – 7x + 1 are
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros = and product of zeros =
= and
= and
Now, we have:
=
=
= 7
If α and β are the zeros of the polynomial f(x) = x2 + x – 2, find the value of
It is given in the question that,
Zeros of the polynomial x2 + x - 2 are
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros = and product of zeros =
= and
= - 1 and
Now, we have:
= ()2
=
=
=
=
() =
If the zeros of the polynomial f(x) = x3 – 3x2 + x + 1 are (a – b), a and (a + b), find the a and b.
It is given in the question that,
Zeros of the polynomial x3 – 3x2 + x + 1 are (a – b), a and (a + b)
Now by using the relationship between the zeros of the quadratic polynomial we have:
Sum of zeros =
a – b + a + a + b =
3a = 3
a =
Now, we have product of zeros =
(a – b) (a) (a + b) =
(1 – b) (1) (1 + b) = - 1
1 – b2 = - 1
b2 = 2
∴ b =
Which of the following is a polynomial?
A. x2 ‒ 5x + 4√x + 3
B. x3/2 – x + x1/2 + 1
C.
D.
We know that, Polynomial is an expression consist of constants, variables and exponents which are connected by addition, subtraction, multiplication and division but the exponent of variables cannot be in fraction and has to be a positive integer.
Hence, option D is correct.
Which of the following is not a polynomial?
A.
B.
C.
D.
We can observe that in the second expression the power of x is -1 but we know that the exponent of the variable in a polynomial has to be a positive term.
Hence, option D is correct.
The zeros of the polynomial x2 – 2x – 3 are
A.‒3, 2
B.‒3, ‒1
C.3, ‒1
D.3, 1
We have, f(x) = x2 – 2x – 3
Now, put f(x) = 0
x2 – 2x – 3 = 0
x2 – 3x + x – 3 = 0
x(x – 3) + 1(x – 3) = 0
(x – 3)(x + 1) = 0
Thus, x = 3, -1
Hence, option C is correct.
The zeros of the polynomial x2 ‒ √2 x – 12 are
A.
B.
C.
D.
We have, f(x) = x2 ‒ √2x – 12
Now, put f(x) = 0
x2 ‒ √2x – 12 = 0
x2 - 3√2x + 2√2x - 12 = 0x(x ‒ 3√2) + 2√2(x – 3√2)=0
(x ‒ 3√2) + (x + 2√2) = 0
Thus, x= 3√2 , -2√2
Hence option B is correct.
The zeros of the polynomial 4x2 + 5√2x – 3 are
A.
B.
C.
D. None of these
We have, f(x) = 4x2 + 5 x – 3
Now, put f(x) = 0
4x2 + 5 x – 3 = 0
4x2 + x -√2x – 3 = 0
2√2x(√2x + 3) -1(√2x + 3) = 0
(2√2x -1) (√2x + 3) = 0
Hence, option C is correct.
The zeros of the polynomial are
A. ‒3, 4
B.
C.
D. None of these
We have, f(x) = x2 + x – 2
f(x) = 6x2 + x – 12 =0
Now, put f(x) = 0
6x2 + x – 12 = 0
6x2 + 9x – 8x – 12 = 0
3x(2x + 3) -4(2x + 3) = 0
Hence, option B is correct.
The zeros of the polynomial are
A.
B.
C.
D. None of these
f(x) = 21x2 – 11x – 2 =0
Now, put f(x) = 0
21x2 – 11x – 2 =0
21x2 – 14x + 3x – 2 =0
7x(3x – 2) + 1 (3x – 2) = 0
(3x – 2) (7x + 1) = 0
Hence, option A is correct.
The sum and the product of the zeros of a quadratic polynomial are 3 and ‒10 respectively. The quadratic polynomial is
A. x2 – 3x + 10
B. x2 + 3x – 10
C. x2 – 3x – 10
D. x2 + 3x + 10
We have, sum of zeroes(α + β) = 3
Product of zeroes(αβ) = -10
We know that,
Required polynomial = x2 – (α + β) + αβ
= x2 – 3x – 10
Hence, option C is correct.
A quadratic polynomial whose zeros are 5 and ‒3, is
A. x2 + 3x + 10
B. x2 – 2x + 15
C. x2 – 2x – 15
D. none of these
We have, α = 5, β = -3
Thus, sum of zeros(α + β) = 5 – 3 = 2
Product of zeros(αβ) = 5(-3) = -15
We know that,
Required polynomial = x2 – (α + β) + αβ
= x2 – 2x – 15
Hence, option C is correct.
A quadratic polynomial whose zeros are , is
A. 10x2 + x + 3
B. 10x2 + x – 3
C. 10x2 – x + 3
D. 10x2 – x – 3
Thus, sum of zeros(α + β)
We know that,
Required polynomial = x2 – (α + β) + αβ
Hence, option D is correct.
The zeros of the quadratic polynomial x2 + 88x + 125 are
A. both positive
B. both negative
C. one positive and one negative
D. both equal
Let the zeros be α and β
We know that, α + β = -88 (sum of zeros)
αβ = 125 (product of zeros)
This is only possible when both the zeroes are negative.
If α and β are the zeros of x2 + 5x + 8 then the value of (α + β) is
A. 5
B. ‒5
C. 8
D. ‒8
Since, α and β are the zeroes of polynomialx2 + 5x + 8
And we know that,
x2 – (α + β) + αβ is the polynomial with α and β as its zeros
Thus, (α + β) = -5
Hence, option B is correct.
If α and β are the zeros of 2x2 + 5x – 9 then the value of αβ is
A.
B.
C.
D.
Since, α and β are the zeroes of polynomial2x2 + 5x – 9
And we know that,
x2 – (α + β) + αβ is the polynomial with α and β as its zeros
Hence, option C is correct.
If one zero of the quadratic polynomial kx2 + 3x + k is 2 then the value of k is
A.
B.
C.
D.
Given: 2 is the zero of the polynomial f(x) = kx2 + 3x + k
Put f(2) = 0
k(2)2 + 3(2) + k = 0
4k + 6 + k = 0
Hence, option D is correct.
If one zero of the quadratic polynomial (k – 1) x2 + kx + 1 is –4 then the value of k is
A.
B.
C.
D.
Given: -4 is the zero of the polynomial f(x) = (k – 1) x2 + kx + 1
Put f(-4) = 0
(k – 1)(-4)2 + k(-4) + 1 = 0
16k -16 – 4k + 1 = 0
Hence, option B is correct.
If –2 and 3 are the zeros of the quadratic polynomial x2 + (a + 1) x + b then
A. a = –2, b = 6
B. a = 2, b = –6
C. a = –2, b = –6
D. a = 2, b = 6
It is given in the question that, -2 and 3 are the zeros of x2 + (a + 1) x + b
∴ (- 2)2 + (a + 1) × (- 2) + b = 0
4 – 2a – 2 + b = 0
b – 2a = - 2 (i)
Also, we have
32 + (a + 1) × 3 + b = 0
9 + 3a + 3 + b = 0
b + 3a = - 12 (ii)
Now, by subtracting the equation (i) from (ii) we get:
a = - 2
Also, b = - 2 – 4 = - 6
If one zero of 3x2 + 8x + k be the reciprocal of the other then k = ?
A. 3
B. –3
C.
D.
Thus, k = 3
Hence, option A is correct.
If the sum of the zeros of the quadratic polynomial kx2 + 2x + 3k is equal
A.
B.
C.
D.
Let the zeros of the polynomial be α and β
According to the question,
α + β = αβ
Hence option D is correct.
If α, β are the zeros of the polynomial x2 + 6x + 2 then ?
A. 3
B. ‒3
C. 12
D. ‒12
Given: α and βare zeros of the given polynomial.
∴α = β= -6 and αβ = 2
Hence, option B is correct.
If α, β, γ are the zeros of the polynomial x3 – 6x2 – x + 30 then (αβ + βγ + γ α) = ?
A. ‒1
B. 1
C. ‒5
D. 30
Given:α, β, γ are the zeros of the polynomial x3 – 6x2 – x + 30
We know that,
Hence, option A is correct.
If α, β, γ are the zeros of the polynomial 2x3 + x2 – 13x + 6 then αβγ = ?
A. ‒3
B. 3
C.
D.
Given: α, β, γ are the zeros of the polynomial 2x3 + x2 – 13x + 6
We know that,
Hence, option A is correct.
If α, β, γ be the zeros of the polynomial p(x) such that (α + β + γ ) = 3, (αβ + βγ + γ α) = ‒10 and αβγ = ‒24 then p(x) = ?
A. x3 + 3x210x + 24
B. x3 + 3x2 10x – 24
C. x3 – 3x2 – 10x + 24
D. None of these
According to the question,
α, β, γ be the zeros of the polynomial p(x)such that (α + β + γ ) = 3, (αβ + βγ + γ α) = ‒10 and αβγ = ‒24
Thus, p(x) = x3 – (α + β + γ )x2 + (αβ + βγ + γ α)x - αβγ
x3 – 3x2 – 10x + 24
Hence, option C is correct.
If two of the zeros of the cubic polynomial az3 + bx2 + cx + d are 0 then in the third zero is
A.
B.
C.
D.
Let5 us assume , -0 and 0 be the zeros of the given polynomial
∴ Sum of zeros =
+ 0 + 0 =
=
∴ The third zero is
Hence, option A is correct
If one of the zeros of the cubic polynomial ax3 + bx2 + cx + d is 0 then the product of the other two zeros is
A.
B.
C. 0
D.
Let us assume and 0 be the zeros of the given polynomial
∴ Sum of the products of zeros taking two at a time is given by:
() =
=
The product of other two zeros will be
Hence, option B is correct
If one of the zeros of the cubic polynomial x3 + ax2 + bx + c is –1 then the product of the other two zeros is
A. a – b – 1
B. b – a – 1
C. 1 – a + b
D. 1 + a – b
It is given in the question that,
- 1 is the zero of the given polynomial x3 + ax2 + bx + c
∴ (- 1)3 + a × (- 1)2 + b × (- 1) + c = 0
a – b + c + 1 = 0
c = 1 – a + b
Also, the product of all zeros is:
× (- 1) = - c
= c
= 1 – a + b
Hence, option C is correct
If α, β be the zeros of the polynomial 2x2 + 5x + k such that then k = ?
A. 3
B. ‒3
C. ‒2
D. 2
It is given in the question that,
are the zeros of the given polynomial 2x2 + 5x + k
= and =
,
=
∴ – =
(-)2 – =
= 1
k = 2
Hence, option D is correct
One dividing a polynomial p(x) by a nonzero polynomial q(x), let g(x) be the quotient and r(x) be the remainder then p(x) = q(x) g(x) + r(x), where
A. r(x) = 0 always
B. deg r(x) <deg g(x) always
C. either r(x) = 0 or deg r(x) <deg g(x)
D. r(x) = g(x)
As, we know that
According to the division algorithm on polynomials, we have
either r (x) = 0 or deg r (x) < deg g (x)
Hence, option C is correct
Which of the following is a true statement?
A. x2 + 5x – 3 is a linear polynomial
B. x2 + 4x – 1 is a binomial.
C. x + 1 is a monomial.
D. 5x3 is a monomial
We know that,
Monomial is that which consist only one term and in the given option we have only one term i.e. 5x2
∴ Option D is correct
Zeros of p(x) = x2 – 2x – 3 are
A. 1, –3
B. 3, –1
C. –3, –1
D. 1, 3
It is given in the question that,
p (x) = x2 – 2x – 3
Let us assume x2 – 2x – 3 = 0
x2 – (3 – 1) x - 3 = 0
x2 – 3x + x – 3 = 0
x (x – 3) + 1 (x – 3) = 0
(x – 3) (x + 1) = 0
x = 3, - 1
If α, β, γ are the zeros of the polynomial x3 – 6x2 – x + 30 then the value of (αβ + βγ + γ α) is
A. ‒1
B. 1
C. ‒5
D. 30
We have,
p (x) = x3 – 6x2 – x + 3
Now we will compare the given polynomial with: x3 – () x2 + () x –
By comparing we get:
() = - 1
If α, β are the zeros of kx2 – 2x + 3k such that α + β = αβ then k = ?
A.
B.
C.
D.
We have,
p (x) = x2 – 2x + 3k
Now by comparing the given polynomial with ax2 + bx + c, we get:
a = 1, b = - 2 and c = 3k
In the question it is given that, are the roots of the given polynomial
∴ =
= -( )
= 2 (i)
:
=
=
= 3k (ii)
Hence, by using (i) and (ii), we have
=
2 = 3k
k =
If is given that the difference between the zeros of 4x2 – 8kx + 9 is 4 and k > 0. Then k = ?
A.
B.
C.
D.
Let us assume the zeros of the polynomial be
We have,
p (x) = 4x2 – 8kx + 9
Now comparing the given polynomial with ax2 + bx + c, we get:
a = 4, b = - 8kx + 9
Sum of roots =
=
2 + 4 = 2k
+ 2 = k
= (k – 2) (i)
, we have product of roots, =
+ 4) =
(k – 2) (k – 2 + 4) =
(k – 2) (k + 2) =
k2 – 4 =
4k2 – 16 = 9
4k2 = 25
k2 =
k =
k =
Find the zeros of the polynomial x2 + 2x – 195.
We have,
p (x) = x2 + 2x – 195
Let us assume p (x) = 0
x2 + (15 – 13) x – 195 = 0
x2 + 15x – 13x – 195 = 0
x (x + 15) – 13 (x + 15) = 0
(x + 15) (x – 13) = 0
x = - 15, 13
Hence, the zeros of the polynomial are -15 and 13
If one zero of the polynomial (a2 + 9) x2 + 13x + 6a is the reciprocal of the other, find the value of a.
We have,
(a + 9) x2 – 13x + 6a = 0
Comparing with standard form of quadratic equation Ax2 + Bx + C
A = (a2 + 9), B = 13 and C = 6a
Let us assume be the zeros of the given polynomial
∴ Product =
=
1 =
a2 + 9 = 6a
a2 – 6a + 9 = 0
a2 – 2 × a × 3 + 32 = 0
(a – 3)2 = 0
a – 3 = 0
a = 3
Find a quadratic polynomial whose zeros are 2 and ‒5.
It is given in the question that the two roots of the given polynomial are 2 and – 5
Let us assume and = - 5
We have:
Sum of Zeros = = 2 + (-5) = - 3
Product of Zeros = = 2 × (-5) = - 10
Hence,
Required polynomial = x2 – (
= x2 – (- 3) x + 10
= x2 + 3x – 10
If the zeros of the polynomial x3 – 3x2 + x + 1 are (a ‒ b), a and (a + b), find the values of a and b
It is given in the question that the roots of the given polynomial are (a – b), a and (a + b)
Now by comparing the given polynomial with Ax3 + Bx2 + Cx + D, we get:
A = 1, B = - 3, C = 1 and D = 1
Now,
(a – b) + a + (a + b) =
3a = -
a = 1
Also, we have:
(a – b) × a × (a + b) =
a (a2 – b2) =
1 (12 – b2) = - 1
1 – b2 = - 1
b2 = 2
b =
Hence, a = 1 and b =
Verify that 2 is a zero of the polynomial x3 + 4x2– 3x – 18.
We have,
p (x) = x3 + 4x2 – 3x – 18
Now,
p (2) = (2)3 + 4 × (2)2 – 3 (2) – 18
= 8 + 16 – 6 – 18
= 24 – 24
= 0
∴ 2 is the zero of the given polynomial
Find the quadratic polynomial, the sum of whose zeros is ‒5 and their products is 6.
It is given in the question that,
Sum of the zeros = - 5
And, product of the zeros = 6
∴ Required polynomial = x2 – (Sum of the zeros) x + Product of the zeros
= x2 – (- 5) x + 6
= x2 + 5x + 6
Find a cubic polynomial whose zeros are 3, 5 and ‒2.
Let us assume be the zeros of the required polynomial
We have,
= 3 + 5 + (- 2) = 6
= 3 × 5 + 5 × (- 2) + (- 2) × 3 = - 1
And, = 3 × 5 × - 2 = - 30
Now, we have:
p (x) = x3 – x2 () + x () –
= x3 – x2 × 6 + x × (- 1) – (- 30)
= x3 – 6x2 – x + 30
Hence, the required polynomial is p (x) = x3 – 6x2 – x + 30
Using remainder theorem, find the remainder when p(x) = x3 + 3x2 – 5x + 4 is divided by (x ‒ 2).
Remainder theorem:
Let p(x) be any polynomial of degree greater than or equal to one and let a be any real number. If p(x) is divided by the linear polynomial x – a, then the remainder is p(a).
It is given in the question that,
p (x) = x3 + 3x2 – 5x + 4
Now, p (2) = (2)3 + 3 (2)2 – 5 (2) + 4
= 8 + 12 – 10 + 4
= 14
Show that (x + 2) is a factor of f(x) = x3 + 4x2 + x – 6.
It is given in the question that,
f (x) = x3 + 4x2 + x – 6
Now, we have
f (- 2) = (- 2)3 + 4 (- 2)2 + (- 2) - 6
= - 8 + 16 – 2 - 6
= 0
Hence, (x + 2) is a factor of f (x)
If α, β, γ are the zeros of the polynomial p(x) = 6x3 + 3x2 – 5x + 1, find the value of .
It is given in the question that,
p (x) = 6x3 + 3x2 – 5x + 1
= 6x3 – (- 3) x2 + (- 5) x – 1
Now by comparing the polynomial with x3 – x2 () + x ( – , we get:
= - 5 and,
= - 1
()
= ()
= ()
= 5
If α, β are the zeros of the polynomial f(x) = x2 – 5x + k such that α ‒ β = 1, find the value of k.
It is given in the question that,
f (x) = x2 – 5x + k such that its coefficients are a = 1, b = - 5 and c = k
∴ =
= 5 (i)
, = 1 (ii)
, we get:
2α = 6
α = = 3
Now putting the value of α in (i), we get
3 + = 5
= 5 – 3 = 2
we know, Product of zeroes=
Hence, k = 6
Show that the polynomial f(x) = x4 + 4x2 + 6 has no zero.
Let us assume t = x2
∴ f (t) = t2 + 4t + 6
Now first of all we have to equate f (t) = 0 in order to find the zeros
∴ t =
=
= - 2
As, t = x2
So, x2 = - 2
x =
We know that, the zeros of the polynomial should be a real number and this is not a real number
∴ f (x) hs no zeros
If one zero of the polynomial p(x) = x3 – 6x2 + 11x – 6 is 3, find the other two zeros.
It is given in the question that,
p (x) = x3 – 6x2 + 11x – 6 having factor (x + 3)
Now, we have to divide p (x) by (x – 3)
x3 – 6x2 + 11x – 6 = (x – 3) (x3 – 3x + 2)
= (x – 3) [(x2 – (2 + 1) x + 2]
= (x – 3) (x2 – 2x – x + 2)
= (x – 3) [x (x – 2) – 1 (x – 2)]
= (x – 3) (x - 1) (x – 2)
Hence, the two zeros of the polynomial are 1 and 2
If two zeros of the polynomial p(x) = 2x4 – 3x3 – 3x2 + 6x – 2 are √2 and – √2, find its other two zeros.
It is given in the question that,
p (x) = 2x4 – 3x3 – 3x2 + 6x – 2 having zeros and -
∴ The polynomial is (x + ) (x - ) = x2 – 2
Let us now divide p (x) by (x2 – 2)
2x4 – 3x3 – 3x2 + 6x – 2 = (x2 – 2) (2x2 – 3x + 1)
= (x2 – 2) [(2x2 – (2 + 1) x + 1]
= (x2 – 2) (2x2 – 2x – x + 1)
= (x2 – 2) [(2x (x – 1) – 1 (x – 1)]
= (x2 – 2) (2x – 1) (x – 1)
Hence, the other two zeros are and 1
Find the quotient when p(X) = 3x4 + 5x3 – 7x2 + 2x + 2 is divided by (x2 + 3x + 1)
It is given in the question that,
p (x) = 3x4 + 5x3 – 7x2 + 2x + 2
Now we have to divide p (x) by (x2 + 3x + 1), we get:
Hence, the quotient is 3x2 – 4x + 2
Use remainder theorem to find the value of k, it being given that when x3 + 2x2 + kx + 3 is divided by (x – 3), then the remainder is 21.
Given: when x3 + 2x2 + kx + 3 is divided by (x – 3), then the remainder is 21.
To find: The value of k.
Solution:
If x-3 divides the equation and leaves 21 as remainder,
it means substituting x=3 in the equation and putting it equal to 21 will
value of k.
Let us assume,
p (x) = x3 + 2x2 + kx + 3
Now, p (3) = (3)3 + 2 (3)2 + 3k + 3
= 27 + 18 + 3k + 3
= 48 + 3k
It is given in the question that the remainder is 21
Hence, 3k + 48 = 21
3k = - 27
k = - 9