r^2 + 6r + -8 = 0
-8 -8
= r^2 + 6r = -8 + 9
(r+3)^2 = 1
I am stuck and the book has my answers to be -2 and -4
You're completing the square rather than factoring. Factoring is finding out which values of and satisfy the equation
Your syntax is confusing, I have assumed the constant term is positive (+8) because that factors.
What two numbers multiply to give +8 and sum to +6