3x2y−[2xy2−2(xy−3/2x2y)+xy]+3xy2.

问题描述:

3x2y−[2xy2−2(xy−

3
2
x2y)+xy]+3xy2

原式=3x2y-(2xy2-2xy+3x2y+xy)+3xy2=3x2y-2xy2+2xy-3x2y-xy+3xy2=xy+xy2