Question 131482
x^2+8x=-16. First add 16 to each side.
x^2+8x+16=0
Find factors of 16 that equal 8
x^2+4x+4x+16
Factor using grouping
x(x+4)+4(x+4)
Check if they have the same binomial in the parentheses. Yes they do.
(x+4)^2=0
Square root both sides
x+4=0
The answer is x=-4