9(x-2y)^3-(x-2y)=(x-2y)(9(x-2y)^2-1)=(x-2y)(3(x-2y)+1)(3(x-2y)-1)=(x-2y)(3x-6y+1)(3x-6y-1)
9(x-2y)3-(x-2y)=(x-2y)[(x-2y)²-1]=(x-2y)(x-2y+1)(x-2y-1)
9(x-2y)³-(x-2y)=(x-2y)[9(x-2y)²-1]=(x-2y)(3x-6y-1)(3x-6y+1)