Question

Factories the following ($2$ to $3$) expressions:
$20x^2-45y^2$

Answer 1

Consider the following question.

$20x^2-45y^2={\left(2\sqrt{5}x\right)}^2-{\left(3\sqrt{5}y\right)}^2$

$=(2\sqrt{5}x-3\sqrt{5}y)(2\sqrt{5}x+3\sqrt{5}y)$

Hence, this is the required answer