5xy²-{2x²y-[3xy²-(xy²-2x²y)]÷（-1/2x

x-y/x²÷x²-2xy+y²/xy*（xy-x²） -3(xy-2x²)-[y²-(5xy-4x²)+2xy] 已知(x+1)²+|y-1|=0,求2(xy-5xy²)-(3xy²-xy)得值 因式分解xy²-2xy+x+2y-1 下列多项式:(1)x²+xy-y²;(2)-x²+2xy-y²;(3)xy+x& 计算：x²+2xy+y²/xy-y².x²-2xy+y²/xy+y&# 计算：(xy-x²)×x-y/xy 3x²y+xy²-[2xy²-4x²y+（x²y-2xy²） 已知x:y=3:2,求(x²+3xy)/(xy+2xy) (2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&# 先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y 2x(x²y-xy²)+xy(xy-x²)]÷x²y等于多少