0.5x²+xy+0.5y²
1-x²+2xy-y²
3x²-4xy+y²
计算:(1).(-2xy²)*(3x²y)²
1、已知xy满足(x+1)²+1y+21=0试求-2xy·5x²y+(0.5x²y&sup
x²-4y²/x²+2xy+y²÷x+2y/2x²+2xy
已知x²y²+x²+y²=10xy-16 求x,y
xy²/(x²y-y) × x²/(x²+x)=
xy²/(x²y) - y×x²/(x²+x)=
x²+xy=12 xy+y²=13
x³y³-x²y²-xy+1
数学分式通分与约分约分 (x²+xy)/(x+y)² x²-y²/(x²
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·