Here is your answer
D) x= -1 or x= 7
REASON:
Given equation-
[tex]{x}^{2}-6x-7=0[/tex]
Split the middle term
[tex] {x}^{2}+x-7x-7=0 [/tex]
Taking common from the terms
[tex] x(x+1)-7(x+1)= 0 [/tex]
[tex] (x+1)(x-7)= 0 [/tex]
Now,
x+1=0 or x-7=0
x= -1 or x= 7
HOPE IT IS USEFUL
