3x²y²+2xy-7x²y²-3/2xy+2+4x²y²,

3x²y+xy²-[2xy²-4x²y+（x²y-2xy²） (2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&# 计算 2xy[4x²y²-3y（xy+x²y）-xy²] x-y/x²÷x²-2xy+y²/xy*（xy-x²） 先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y 化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y² -3(xy-2x²)-[y²-(5xy-4x²)+2xy] -4x²y-8xy²+2x²y-3xy² 计算：（-7x²y）（2x²y-3xy³+xy） 计算3x[xy-2x(1/y-x/3]+3y(x²-y²) 急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy) 计算：x²+2xy+y²/xy-y².x²-2xy+y²/xy+y&#