Answer:
{- 11, - 1 }
Step-by-step explanation:
Since the coefficient of the x² term is 1 , to complete the square
add (half the coefficient of the x-term )² to both sides
x² + 2(6)x + 36 = - 11 + 36 ← complete the square on the left side
(x + 6)² = 25 ( take the square root of both sides
= ±
x + 6 = ± 5 ( subtract 6 from both sides )
x = - 6 ± 5
x = - 6 + 5 = - 1 or x = - 6 - 5 = - 11