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

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Answer 1 · 2015-07-03T16:31:44

$4x^4 - y^2 =color(blue)((2x^2+y)(2x^2-y)$

$4x^4 - y^2$ is of the form $color(blue)(a^2 - b^2$ (where $a=2x^2 , b=y)$ , and as per the identity:
$color(blue)(a^2 - b^2= (a+b)(a-b)$

So, $4x^4 - y^2 =color(blue)((2x^2+y)(2x^2-y)$ .

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