How do you solve $x^2-8x=9$ ?

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Answer 1 · 2018-06-16T21:45:16

See a solution process below:

First, put the equation in standard form:

$x^2 - 8x = 9$

$x^2 - 8x - color(red)(9) = 9 - color(red)(9)$

$x^2 - 8x - 9 = 0$

Next, factor the left side of the equation as:

$(x + 1)(x - 9) = 0$

Now, solve each term on the left side of the equation for $0$ :

Solution 1:

$x + 1 = 0$

$x + 1 - color(red)(1) = 0 - color(red)(1)$

$x + 0 = -1$

$x = -1$

Solution 2:

$x - 9 = 0$

$x - 9 + color(red)(9) = 0 + color(red)(9)$

$x - 0 = 9$

$x = 9$

The Solution Set Is:

$x = {-1, 9}$

How do you solve x^2-8x=9x^2-8x=9?