# How do you multiply (x-1) (x+4) (x-3)?

Apr 18, 2015

Multiply the terms two at a time:
$\left(x - 1\right) \left(x + 4\right)$
$= \left(x - 1\right) \cdot x + \left(x - 1\right) \cdot 4$

$= {x}^{2} - x + 4 x - 4$

$= {x}^{2} + 3 x - 4$

therefore
$\left(x - 1\right) \left(x + 4\right) \left(x - 3\right)$
$= \left({x}^{2} + 3 x - 4\right) \left(x - 3\right)$

$= \left({x}^{2} + 3 x - 4\right) \cdot x - \left({x}^{2} + 3 x - 4\right) \cdot 3$

$= \left({x}^{3} + 3 {x}^{2} - 4 x\right) - \left(3 {x}^{2} + 9 x - 12\right)$

$= {x}^{3} - 13 x + 12$