3x的平方y-{2xy-2{xy-2分之3x的平方y}+xy
问题描述:
3x的平方y-{2xy-2{xy-2分之3x的平方y}+xy
答
3x²y-{2xy-2(xy-3/2x²y)}+xy
=3x²y-{2xy-2xy+3/2x²y}+xy
=3x²y-2xy+2xy-3/2x²y+xy
=xy