计算 ①[x(x²y²-xy)-y(x²-x³y)]÷3x²y

x³y³-x²y²-xy+1 计算:(1).(-2xy²)*(3x²y)² 3x²-4xy+y² (x+y)²-（x³+y³)÷（x+y) 先化简,再求值：3xy²(-x²y+2x³y²)-4xy(-xy²)· 已知x/y=3,求x²+2xy-3y²/x²-xy+y³的值 x²-4y²/x²+2xy+y²÷x+2y/2x²+2xy 1-x²+2xy-y² 已知x²y²+x²+y²=10xy-16 求x,y xy²/(x²y-y) × x²/(x²+x)= xy²/(x²y) - y×x²/(x²+x)= |x+2y+3|+(2x+y)²=0求x²-xy+y²