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Solve the quadratic equation x2 + 14x = 51 by completing the square.
Question 3 options:

A)

x = –17, x = –3

B)

x = –17, x = 3

C)

x = 3, x = 17

D)

x = –3, x = 17

Respuesta :

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 = ± [tex]\sqrt{100}[/tex] = ± 10 ( subtract 7 from both sides )

x = - 7 ± 10

Thus

x = - 7 - 10 = - 17

x = - 7 + 10 = 3

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