Question

If one zero of the quadratic polynomial 4x^2 + kx - 1 is 1, then what is the value of k?​

Answer 1

Step-by-step explanation:

p(x)=4x²+kx-1

p(1)=0

4×1²+k×1-1=0

4+k-1=0

3+k=0

k=(-3)

Answer 2

Step-by-step explanation:

Given:-

One zero of the quadratic polynomial 4x^2 + kx - 1 is 1.

To find:-

what is the value of k?

Solution:-

Given quadratic polynomial is 4x^2+kx-1

Let P(x)=4x^2+kx-1

Given zero of P(x)=1

If 1 is the zero of P(x) then it satisfies the given P(x) .i.e. P(1)=0

Put x = 1 in P(x) then

P(1)=4(1)^2+k(1)-1=0

=>4(1)+k-1=0

=>4+k-1=0

=>k+3 = 0

=>k = -3

Therefore, k = -3

Answer:-

The value of k for the given problem is -3

Check:-

If k = -3 then the P(x) becomes

4x^2-3x-1

=>4x^2-4x+x-1

=>4x(x-1)+1(x-1)

=>(x-1)(4x+1)

To get zeroes we write P(x)=0

=>(x-1)(4x+1)=0

=>x-1 = 0 or 4x+1 = 0

=>x = 1 or x = -1/4

1 is the one of the zeroes of the given Polynomial

Verified the given relation.

Used Concept:-

• The value which satisfies the given Polynomial is called its zero or solution.