-5x³y(x-y)³+20y[x²(y-x)]²=-5x³y(x-y)³ +20yx⁴(x-y)²=-5x³y(x-y)²[(x-y)-4x]=-5x³y(x-y)²(-3x-y)=5x³y(x-y)²(3x+y)