Question

For what value of k, (–4) is a zero of the polynomial x2 – x – (2k + 2)?

Answer 1

Answer:

k = 9

Step-by-step explanation:

Given: -4 is one of zeroes of the polynomial x2 ‒ x- (2k + 2), which means x = -4 will satisfy it. The value of k is 9.

Answer 2

In the given polynomial f(x)=x^2−x−(2k+2), substitute x=−4 as shown below:

• f(−4)=(−4)^2−(−4)−(2k+2)=16+4−2k−2=18−2k

• Therefore, f(−4)=18−2k.

• Since it is given that x=−4 is a zero of the polynomial f(x)=x^2−x−(2k+2),         therefore f(−4)=0 that is:

• 18−2k=0

⇒  2k=18

⇒k=218

⇒k=9

• Hence k=9.