# What is the standard form of y= (x – 1) (x -5) (x + 3) ?

Jul 17, 2018

$y = {x}^{3} - 3 {x}^{2} - 13 x + 15$

#### Explanation:

Given: $y = \left(x - 1\right) \left(x - 5\right) \left(x + 3\right)$

Distribute the first two factors using FOIL :

$y = \left({x}^{2} - 5 x - 1 x + 5\right) \left(x + 3\right)$

Add like terms: $\text{ } y = \left({x}^{2} - 6 x + 5\right) \left(x + 3\right)$

FOIL again:

$y = {x}^{3} - 6 {x}^{2} + 5 x + 3 {x}^{2} - 18 x + 15$

Add like terms: $\text{ } y = {x}^{3} - 3 {x}^{2} - 13 x + 15$