Factor 4a^2-100

$4 a^{2} - 100$

Step 1

Factor $4$ out of $4 a^{2} - 100$ .

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

$4 (a^{2}) - 100$

Factor $4$ out of $- 100$ .

$4 a^{2} + 4 \cdot - 25$

Factor $4$ out of $4 a^{2} + 4 \cdot - 25$ .

$4 (a^{2} - 25)$

Step 2

Rewrite $25$ as $5^{2}$ .

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

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 $b = 5$ .

$4 ((a + 5) (a - 5))$

Remove unnecessary parentheses.

$4 (a + 5) (a - 5)$