Factor a^2-4

$a^{2} - 4$

Step 1

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

$a^{2} - 2^{2}$

Step 2

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

$(a + 2) (a - 2)$