Factor 5a^2-20

$5 a^{2} - 20$

Step 1

Factor $5$ out of $5 a^{2} - 20$ .

Factor $5$ out of $5 a^{2}$ .

$5 (a^{2}) - 20$

Factor $5$ out of $- 20$ .

$5 a^{2} + 5 \cdot - 4$

Factor $5$ out of $5 a^{2} + 5 \cdot - 4$ .

$5 (a^{2} - 4)$

Step 2

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

$5 (a^{2} - 2^{2})$

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 $a = a$ and $b = 2$ .

$5 ((a + 2) (a - 2))$

Remove unnecessary parentheses.

$5 (a + 2) (a - 2)$