Question

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

Answer 1

p(x) = x^2-x-(2k+2)                                                         when x = -4
p(-4) = (-4)^2-(-4)-(2k+2)                                                 p(-4)=0 [given]
0 = 8+4-2k-2
0 = 12-2k-2
0 = 10-2k
2k=10
k = 10/2
k=5

Answer 2

-4 is a
 zero of polynomial f(x) = x^2-x-(2k+2)
f(-4)=0
16+4-2k-2=0
2k=18
k=9