Question

#4: Solve the quadratic equation below by completing the square. Select

all solutions. *
x2 + 16x = -39

O 13
O 9
O 8
O 3
O -3
O -8
O -9
O -13

Answer 1

x = - 13, x = - 3

Explanation:

Given

x² + 16x = - 39

To complete the square

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

x² + 2(8)x + 64 = - 39 + 64

(x + 8)² = 25 ( take the square root of both sides )

x + 8 = ±
`√(25)` = ± 5 ( subtract 8 from both sides )

x = - 8 ± 5, thus

x = - 8 - 5 = - 13 or x = - 8 + 5 = - 3