Question 800930
(k-1)(k+7)=9

{{{k^2+6x-7=9}}}


{{{k^2+6x=9+7}}}


{{{k^2+6x+9=9+7+9}}}


{{{(k+3)^2=25}}}


take the square root

(x+3)=+/- 5

x=-3+5=2

OR
x=-3-5=-8

x=2OR -8