# Which are the solutions to x^2+9x=36?

Dec 8, 2016

$x = - 12$
$x = 3$

#### Explanation:

${x}^{2} + 9 x = 36$

Subtract 36 from each side:
${x}^{2} + 9 x - 36 = 0$

Two numbers that multiply to $- 36$ and add to $9$ are: $- 3$ and $12$

${x}^{2} - 3 x + 12 x - 36 = 0$

$x \left(x - 3\right) + 12 \left(x - 3\right) = 0$

$\left(x + 12\right) \left(x - 3\right) = 0$

$x = - 12$
$x = 3$