Algebra Examples

$49 x^{2} - 81$

Step 1

Rewrite $49 x^{2}$ as ${(7 x)}^{2}$ .

${(7 x)}^{2} - 81$

Step 2

Rewrite $81$ as $9^{2}$ .

${(7 x)}^{2} - 9^{2}$

Step 3

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = 7 x$ and $b = 9$ .

$(7 x + 9) (7 x - 9)$