Answer
(x +3y) (x - 3y) (x + y) (x - y)
Work Step by Step
$x^{4}$ - 10$x^{2}$$y^{2}$ + 9$y^{4}$
= $x^{4}$ -$x^{2}$$y^{2}$ - 9$x^{2}$$y^{2}$ + 9$y^{4}$
= $x^{2}$ ($x^{2}$-$y^{2}$) - 9$y^{2}$($x^{2}$ - $y^{2}$)
= ($x^{2}$ - 9$y^{2}$) ($x^{2}$ - $y^{2}$)
Use formula (($x^{2}$ - $y^{2}$) = (x + y) (x - y)}
($x^{2}$ - 9$y^{2}$) ($x^{2}$ - $y^{2}$) = (x +3 y) (x - 3 y) (x + y) (x - y)
Answer = (x +3 y) (x - 3 y) (x + y) (x - y)
