Answer:
x = - 10, x = - 2
Step-by-step explanation:
Given
x² + 12x = - 20
To complete the square
add (half the coefficient of the x- term )² to both sides
x² + 2(6)x + 6² = - 20 + 6² ← completing the square
(x + 6)² = - 20 + 36 = 16
Take the square root of both sides
x + 6 = ± [tex]\sqrt{16}[/tex] = ± 4
Subtract 6 from both sides
x = - 6 ± 4, hence
x = - 6 - 4 = - 10 or x = - 6 + 4 = - 2
