Solve 3x^2=-12-6x by completing the square

x = - 1 ± i

Step-by-step explanation:

Given

3x² = - 12 - 6x ( add 6x to both sides )

3x² + 6x = - 12 ( divide through by 3 )

x² + 2x = - 4

To complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(1)x + 1 = - 4 + 1

(x + 1)² = - 3 ( take the square root of both sides )

x + 1 = ± = ± i ( subtract 1 from both sides )

x = - 1 ± i