Question

hi PLLSS HELP solve x2 – 8x = 20 by completing the square. Which is the solution set of the equation? {–22, 14} {–14, 22} {–10, 2} {–2, 10}

Answer 1

Answer:

{ - 2, 10 }

Step-by-step explanation:

Given

x² - 8x = 20

To complete the square

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

x² + 2(- 4)x + 16 = 20 + 16, that is

(x - 4)² = 36 ( take the square root of both sides )

x - 4 = ± $\sqrt{36}$ = ± 6 ( add 4 to both sides )

x = 4 ± 6

Thus

x = 4 - 6 = - 2

x = 4 + 6 = 10