3x的平方y-中括号2xy-2(xy-三分之二x的平方y)+xy中括号
=3x²y-(2xy-2xy+4/3x²y+xy)
=3x²y-(4/3x²y+xy)
=3x²y-4/3x²y-xy
=5/3x²y-xy
=-5/3*3²*1/3+3x1/3
=-5+1
=-4
3x的平方y-中括号2xy-2(xy-三分之二x的平方y)+xy中括号
=3x²y-(2xy-2xy+4/3x²y+xy)
=3x²y-(4/3x²y+xy)
=3x²y-4/3x²y-xy
=5/3x²y-xy
=-5/3*3²*1/3+3x1/3
=-5+1
=-4