Answer:
x = - 16, x = - 4
Explanation:
Given
x² + 20x + 100 = 36 ( subtract 36 from both sides )
x² + 20x + 64 = 0
Consider the factors of the constant term (+ 64) which sum to give the coefficient of the x- term (+ 20)
The factors are 16 and 4, since
16 × 4 = 64 and 16 + 4 = 20, thus
(x + 16)(x + 4) = 0
Equate each factor to zero and solve for x
x + 16 = 0 ⇒ x = - 16
x + 4 = 0 ⇒ x = - 4