Basic Math Examples

$a^{2} - 81 b^{2}$

Step 1

Rewrite $81 b^{2}$ as ${(9 b)}^{2}$ .

$a^{2} - {(9 b)}^{2}$

Step 2

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

$(a + 9 b) (a - (9 b))$

Step 3

Multiply $9$ by $- 1$ .

$(a + 9 b) (a - 9 b)$