[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]/2(x-y)^2的解题过程是什么

[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]/2(x-y)^2
=2(x-y)^2[2(x-y)-4(x+y)+3y]/2(x-y)^2
=2(x-y)-4(x+y)+3y
=2x-2y-4x-4y+3y
=2x-4x-2y-4y+3y
=-2x-3y