How do you solve the quadratic equation by completing the square: $x^2-8x=9$ ?

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Answer 1 · 2015-08-01T00:14:08

Solve y = x^2 - 8x = 9

$x^2 - 8x + 16 = 9 + 16 = 25$
$(x - 4)^2 = 25$
$(x - 4) = +- 5$
$x = 4 +-5$ --> $x = (-1)$ and $x = 9$

How do you solve the quadratic equation by completing the square: x^2-8x=9x^2-8x=9?