Factor 4w^2-81

$4 w^{2} - 81$

Step 1

Rewrite $4 w^{2}$ as ${(2 w)}^{2}$ .

${(2 w)}^{2} - 81$

Step 2

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

${(2 w)}^{2} - 9^{2}$

Step 3

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

$(2 w + 9) (2 w - 9)$