Find the value

$=10 x y\left(x^{3}-y^{3}\right)$

$=10 x y(x-y)\left(x^{2}+x y+y^{2}\right)$

$\therefore\left[x^{3}-y^{3}=(x-y)\left(x^{2}+x y+y^{2}\right)\right]$

$\therefore 10 x^{4} y-10 x y^{4}=10 x y(x-y)\left(x^{2}+x y+y^{2}\right)$