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

3x²y-{2xy-2(xy-3/2x²y)}+xy
=3x²y-{2xy-2xy+3/2x²y}+xy
=3x²y-2xy+2xy-3/2x²y+xy
=xy