Question

Ryan needs to solve the equation x2−8x−9=0 by completing the square. Which pair of steps is the most efficient way to begin?

Answer 1

x^2 - 8x - 9 = 0
x^2 - 8x = 9
(x - 4)^2 - 16 = 9
(x - 4)^2 = 25

x - 4 = +/- sqrt25 = +/- 5

x = 5 + 4, -5 + 4

Solution set is {-1, 9}

Answer 2

^2−8=9

^2−8+16=9+16

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