# How do you solve 8x - x^2 = 15?

Jan 22, 2016

Re-write the equation in standard form; then factor to get
$\textcolor{w h i t e}{\text{XXX}} x = 3$ or $x = 5$

#### Explanation:

$8 x - {x}^{2} = 15$

$\Leftrightarrow {x}^{2} - 8 x + 15 = 0$

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

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