Factor 4x^2-36

$4 x^{2} - 36$

Step 1

Factor $4$ out of $4 x^{2} - 36$ .

Factor $4$ out of $4 x^{2}$ .

$4 (x^{2}) - 36$

Factor $4$ out of $- 36$ .

$4 x^{2} + 4 \cdot - 9$

Factor $4$ out of $4 x^{2} + 4 \cdot - 9$ .

$4 (x^{2} - 9)$

Step 2

Rewrite $9$ as $3^{2}$ .

$4 (x^{2} - 3^{2})$

Step 3

Factor.

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = x$ and $b = 3$ .

$4 ((x + 3) (x - 3))$

Remove unnecessary parentheses.

$4 (x + 3) (x - 3)$