Question

Solve the quadratic equation x2 + 14x = 51 by completing the square.

Answer 1

Answer:

B

Step-by-step explanation:

Given

x² + 14x = 51

To complete the square

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

x² + 2(7)x + 49 = 51 + 49 , that is

(x + 7)² = 100 ( take the square root of both sides )

x + 7 = ± $\sqrt{100}$ = ± 10 ( subtract 7 from both sides )

x = - 7 ± 10

Thus

x = - 7 - 10 = - 17

x = - 7 + 10 = 3