Question

If 5 is a zero of the quadratic polynomial, x2 – kx – 15 then the value of k is​

Answer 1

Answer: k= 2

Step-by-step explanation:

putting value of x as 5

then

p(x)=x^2-kx-15=0

=(5)^2-k(5)-15=0

=25-5k-15=0

=10-5k=0

=-5k=-10

=k=-10/-5

=k=2

Answer 2

Given:

Polynomial: x2 –kx – 15

Zero of polynomial=5

To find:

The value of k

Solution:

The required value of k is 2.

We can determine the value of substituting the zero's value in the given polynomial.

We know that the polynomial's zero is the x's value that makes the polynomial equal to 0.

So, the value of the zero=x=5

The given polynomial: x2–kx– 15

On putting x=5, we get

=$5^{2}$-5k-15

=25-15-5k

=10-5k

Now, this is equal to 0.

So, 10-5k=0

On solving,

10=5k

10/5=k

2=k

Therefore, the required value of k is 2.