(2x+y)³-(x-2y)³
=((2x+y)-(x-2y))((2x+y)^2-(2x+y)(x-2y)-(x-2y)^2)
=(2x+y-x+2y)(4x^2+4xy+y^2-2x^2+4xy-xy+2y^2-x^2+4xy+4y^2)
=(x+3y)(x^2+11xy+7y^2)
因式分解 -4x³y+16x²y²-16xy³
=-4xy(x^2-4xy+4y^2)
=-4xy(x-2y)^2
(2x+y)³-(x-2y)³
=((2x+y)-(x-2y))((2x+y)^2-(2x+y)(x-2y)-(x-2y)^2)
=(2x+y-x+2y)(4x^2+4xy+y^2-2x^2+4xy-xy+2y^2-x^2+4xy+4y^2)
=(x+3y)(x^2+11xy+7y^2)
因式分解 -4x³y+16x²y²-16xy³
=-4xy(x^2-4xy+4y^2)
=-4xy(x-2y)^2