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