Answer:
x = -2 ±√13
Step-by-step explanation:
To complete the square, take the middle term bx and divide it in two. Then take the square.
x^2 + 4x - 9 has bx = 4x. Take 4/2 = 2. Square 2^2 = 4.
Now to finish completing the square add 4 to each side.
x^2 + 4x - 9 = 0
x^2 + 4x + 4 - 9 = 4
(x+2)^2 -9 = 4
Add 9 to both sides and take the square root of each side to solve.
(x+2)^2 = 13
(x+2) = ± √13
x = -2 ±√13
