问题
解答题
先化简再求值:3x2y-[2xy2-2(xy-1.5x2y)+xy]+2xy2,其中x=-3,y=-2.
答案
原式=3x2y-(2xy2-2xy+3x2y+xy)+2xy2
=3x2y-2xy2+2xy-3x2y-xy+2xy2
=xy,
当x=-3,y=-2时,原式=(-3)×(-2)=6.
先化简再求值:3x2y-[2xy2-2(xy-1.5x2y)+xy]+2xy2,其中x=-3,y=-2.
原式=3x2y-(2xy2-2xy+3x2y+xy)+2xy2
=3x2y-2xy2+2xy-3x2y-xy+2xy2
=xy,
当x=-3,y=-2时,原式=(-3)×(-2)=6.