Algebra Examples

$x^{2} - 400$

Step 1

Rewrite $400$ as $20^{2}$ .

$x^{2} - 20^{2}$

Step 2

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = x$ and $b = 20$ .

$(x + 20) (x - 20)$