Precalculus Examples

$\frac{1}{x^{2} - 9}$

Step 1

Rewrite $9$ as $3^{2}$ .

$\frac{1}{x^{2} - 3^{2}}$

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 $b = 3$ .

$\frac{1}{(x + 3) (x - 3)}$