Factor $$ (x^2+y^2)^2-4x^2y^2 $$

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Uniteasy Admin · Accepted Answer

Transform to the patter of the difference of squares
$$ (x^2+y^2)^2-4x^2y^2 $$
$$=(x^2+y^2)^2-(2xy)^2$$
$$=(x^2+y^2-2xy)(x^2+y^2+2xy) $$
$$=(x-y)^2(x+y)^2$$

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