# What is the standard form of y= (x – 1) (x + 2) (x + 3) ?

May 11, 2017

$y = {x}^{3} + 4 {x}^{2} - 9$

#### Explanation:

Expand the formula and ensure the power and coefficient go first.

$y = \left(x - 1\right) \left(x + 2\right) \left(x + 3\right)$
$= \left({x}^{2} + 2 x - x - 3\right) \left(x + 3\right)$ (Use FOIL on the first two terms)
$= \left({x}^{2} + x - 3\right) \left(x + 3\right)$ (Simplify)
$= {x}^{2} \left(x + 3\right) + x \left(x + 3\right) - 3 \left(x + 3\right)$ (Distribute the $\left(x + 3\right)$)
$= {x}^{3} + 3 {x}^{2} + {x}^{2} + 3 x - 3 x - 9$
$= {x}^{3} + 4 {x}^{2} - 9$ (Simplify)