题目应是 [(3x-2y)^2-(3x+2y)^2+3x^2y^2]/2xy
=[(3x-2y+3x+2y)(3x-2y-3x-2y)+3x^2y^2]/2xy
=[6x*(-4y)+3x^2y^2]/2xy
=[-24xy+3x^2y^2]/2xy
=(-24+3xy)/2