# How do you factor 2x^2- 18?

Sep 28, 2015

The answer is $2 \left(x + 3\right) \left(x - 3\right)$ .

#### Explanation:

$2 {x}^{2} - 18$

Factor out the GCF $2$.

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

${x}^{2} - 9$ fits the form ${a}^{2} - {b}^{2}$, where $a = x \mathmr{and} b = 3$.

Rewrite the expression.

$2 \left({x}^{2} - {3}^{2}\right)$

${a}^{2} - {b}^{2} = \left(a + b\right) \left(a - b\right)$

$2 \left(x + 3\right) \left(x - 3\right)$