# How do you solve x^2 = 2x + 15?

Apr 9, 2016

$x = - 3$ or $x = 5$

#### Explanation:

${x}^{2} = 2 x + 15$

$\Leftrightarrow {x}^{2} - 2 x - 15 = 0$

Splitting the middle term in $- 5 x$ and $3 x$ we get

${x}^{2} - 5 x + 3 x - 15 = 0$ or

$x \left(x - 5\right) + 3 \left(x - 5\right) = 0$ or

$\left(x + 3\right) \left(x - 5\right) = 0$

Hence $x = - 3$ or $x = 5$