Factor 81w^2-49 - Math solver

$81 w^{2} - 49$

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

${(9 w)}^{2} - 49$

Rewrite $49$ as $7^{2}$ .

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

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

$(9 w + 7) (9 w - 7)$

Factor 81w^2-49