5xy²-{2x²y-[3xy²-(4xy²-2xy²)]}=
问题描述：
5xy²-{2x²y-[3xy²-(4xy²-2xy²)]}=
答
5xy²-{2x²y-[3xy²-(4xy²-2xy²)]}=5xy²-[2x²y-(3xy²-4xy²+2xy²)]=5xy²-(2x²y-3xy²+4xy²-2xy²)=5xy²-2x²y+3xy²-4xy²...