How do you factor completely $4x^2 - 9y^2$ ?

Question

22364 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-11-17T10:15:45

$color(blue)((2x+3y)(2x-3y)$ is the factorised form of the expression

$4x^2-9y^2$ can be also written as $(2x)^2-(3y)^2$

Now, as per identity:
$color(blue)(a^2-b^2=(a+b)(a-b)$

So , in case of our expression
$color(blue)(a=2x, b=3y$

$(2x)^2-(3y)^2=color(blue)((2x+3y)(2x-3y)$

How do you factor completely 4x^2 - 9y^24x^2 - 9y^2?