Factor r^2-4

$r^{2} - 4$

Step 1

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

$r^{2} - 2^{2}$

Step 2

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 $b = 2$ .

$(r + 2) (r - 2)$