Answer:
(x + 5)² = - 3
Explanation:
Given
x² + 22x + 28 = 12x ( subtract 12x from both sides )
x² + 10x + 28 = 0 ( subtract 28 from both sides )
x² + 10x = - 28
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(5)x + 25 = - 28 + 25
(x + 5)² = - 3