m(2x+y)²-m(x+2y)²

问题描述:

m(2x+y)²-m(x+2y)²

原式
=m×[(2x+y)²-(x+2y)²]
=m×(2x+y+x+2y)(2x+y-x-2y)
=m×(3x+3y)(x-y)
=3m(x+y)(x-y)