Question 576034
{{{x^4y-81y^5 }}}
Factor out y
{{{y(x^4-81y^4)}}}
The difference of squares will factor to
{{{y(x^2-9y^2)(x^2+9y^2)}}}
one more difference of squares
{{{y(x+3y)(x-3y)(x^2+9y^2)}}}