Factor polynomial $$ 81x^{2}-y^{2} $$
Answer
$$ 81x^{2}-y^{2} = (9x+y)(9x-y) $$
Explanation
Rewrite $ 81x^2-y^2 $ as:
$$ \color{blue}{ 81x^2-y^2 = (9x)^2 - (y)^2 } $$Now we can apply the difference of squares formula.
$$ I^2 - II^2 = (I - II)(I + II) $$After putting $ I = 9x $ and $ II = y $ , we have:
$$ 81x^2-y^2 = (9x)^2 - (y)^2 = ( 9x-y ) ( 9x+y ) $$This page was created using
Polynomial Factoring Calculator