SOLUTION: complete the square x^2+12x=9

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Question 621485: complete the square x^2+12x=9
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
complete the square
x^2+12x=9
take half 'b', square it and add to both sides:
x^2+12x+36 = 9+36
x^2+12x+36 = 45
(x+6)(x+6) = 45
(x+6)^2 = 45
x+6 = sqrt(45)
x+6 = +-sqrt(3*3*5)
x+6 = +-3sqrt(5)
x = -6+-3sqrt(5)