Question

Solve x2 + 12x = –11 by completing the square. Which is the solution set of the equation?

Answer 1

Explanation:

x2 + 12x = –11

x2 + 12x +36 = –11 + 36

(x+6)^2 = -11 + 36 = 25 = (+/- 5)^2

x+6 = +/- 5

x+6 = +5 => x=-1

x+6 = -5 => x = -11

So the solution set is S = {-1, -11}

Answer 2

you add the 11 back to the other side making it x^2+12x+11=0

then you factor it

(x+11)(x+1)

you should know what to do from here