# How do you completely factor x^3 + 4x^2 - 45x?

Jun 12, 2018

$x \left(x - 5\right) \left(x + 9\right)$

#### Explanation:

take the $x$ as a common factor such that:

$x \left({x}^{2} + 4 x - 45\right)$

factorize the expression inside the brackets

$x \left({x}^{2} + 9 x - 5 x - 45\right)$

$x \left(x \left(x + 9\right) - 5 \left(x + 9\right)\right)$
$x \left(x - 5\right) \left(x + 9\right)$