Factor 100-4x^2

$100 - 4 x^{2}$

Step 1

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

Factor $4$ out of $100$ .

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

Factor $4$ out of $- 4 x^{2}$ .

$4 (25) + 4 (- x^{2})$

Factor $4$ out of $4 (25) + 4 (- x^{2})$ .

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

Step 2

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

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

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 $a = 5$ and $b = x$ .

$4 ((5 + x) (5 - x))$

Remove unnecessary parentheses.

$4 (5 + x) (5 - x)$