化简(2x+3y)(x-y)-(y+2x)(2x-y)

问题描述:

化简(2x+3y)(x-y)-(y+2x)(2x-y)

=2x^2-2xy+3xy-3y^2-(2xy-y^2+4x^2-2xy)
=2x^2+xy-3y^2-4x^2+y^2
=xy-2y^2-2x^2