Question

For what values of k,-4 is a zero of the poynomial x^2-x-(2k+2)?

Answer 1

Given -4 is the zero of polynomial.( it means the value of equation is zero when x=-4)

i.e, x=-4…., substitute this in the equation x^2-x-(2k+2)

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

16+4-(2k+2)=0

20–2k-2=0

18–2k=0

2k=18

k=18/2

k=9

there fore, -4 is the zero of polynomial for value of k is 9

@skb

Answer 2

Given : The value of X which is (-4)

To find : The value of k

Equation :  x^2-x-(2k+2)

Zero of the polynomial,

x^2-x-(2k+2) = 0

Let's substitute the value of x,

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

16 + 4 - ( 2 k + 2 ) = 0

20 - 2k - 2 = 0

18 - 2k = 0

2k = 18

k = $\frac{18}{2}$

k = 9

Verification :

(-4)^2 - (-4) - ( 2 (9) + 2)

16 + 4 - ( 2 (9) + 2)

18 - 18

= 0

Hence, the value of k is 9