# How do you factor completely 7y^3 - 21y^2 - 2y + 6?

Dec 26, 2015

= color(green)((7y^2-2)(y-3)

#### Explanation:

color(blue)(7y^3-21y^2)color(green)(-2y+6

Factorising by grouping :

$\left(7 {y}^{2}\right)$ is common to both the terms in the first group, and $- 2$ is common to both the terms in the second group:

We can factor this expression by making groups of two terms:
$7 {y}^{2} \left(y - 3\right) - 2 \left(y - 3\right)$

$y - 3$ is common to both the terms now:

= color(green)((7y^2-2)(y-3)