5x^3y(x-y)^3-10x^4y^3(y-x)^2

5x^3y(x-y)^3-10x^4y^3(y-x)^2

5x^3y(x-y)^3-10x^4y^3(y-x)^2
=5x³y(x-y)³-10x^4y³(x-y)²
=5x³y(x-y)²(x-y-2xy²)