通分：1/x²-y²,1/x²+xy,今晚就要啊,

1-x²+2xy-y² 计算:(1).(-2xy²)*(3x²y)² 数学分式通分与约分约分 (x²+xy)/(x+y)² x²-y²/（x² 一道数学通分题2xy/(x+y)²与x/x²-y² x³y³-x²y²-xy+1 分式的约分与通分问题约分 (x²+xy)/(x+y)² x²-y²/（x&sup 1 3x²+4xy-y²= (-3x²y)(1/3xy²)答案? 方程组{x²+y²=10(1)x²-3xy+2y²=0(2)怎么解 3x²-4xy+y² (x+y-2xy)(x+y-2)+(1-xy)² 越快越好（1）(xy²+3)(xy²+3)-2x(-x+y)（2）(x+2)(x²+4)(