Factor 4r^2-64

$4 r^{2} - 64$

Step 1

Factor $4$ out of $4 r^{2} - 64$ .

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

$4 (r^{2}) - 64$

Factor $4$ out of $- 64$ .

$4 r^{2} + 4 \cdot - 16$

Factor $4$ out of $4 r^{2} + 4 \cdot - 16$ .

$4 (r^{2} - 16)$

Step 2

Rewrite $16$ as $4^{2}$ .

$4 (r^{2} - 4^{2})$

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 $a = r$ and $b = 4$ .

$4 ((r + 4) (r - 4))$

Remove unnecessary parentheses.

$4 (r + 4) (r - 4)$