Question

the value of k for which -4 is a zero of the polynomial x^2-x(2k+2) is (a)3 (b)9 (c)6 (d)-1​

Answer 1

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

16+8k-8=0

8+8k=0

8k=-8

k=-8/8

k=-1

Answer 2

Answer:

${( - 4)}^{2} - ( - 4)(2k + 2) = 0 \\ \\ 16 + 4(2k + 2) = 0 \\ \\ 16 + 8k + 8 = 0 \\ \\ 8k = - 24 \\ \\ k = - 3$