Question

Solve x^2+4x−39=0
by completing the square. If necessary, write your answer in simplest radical form.(2 points)

Answer 1

x^2 + 4x − 39 = 0
Complete the square: x^2 + 4x + 4 − 4 − 39 = 0 ⇒ (x + 2)^2 − 43 = 0
So (x + 2)^2 = 43 ⇒ x + 2 = ±√43 ⇒ x = −2 ± √43.