x/x^2-y^2与2y/x^2+xy 通分

2xy/(x+y)^与x/x^-y^ 2xy/(x+y)(x+y)与x/(x+y)(x-y)怎么通分 (-x-y)(x^2+xy+y^2) 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) （x^2+xy/x-y)/（xy/x-y)计算 X-Y/2X+2Y XY/X+Y² 因式分解：x×x-xy-2y×y-x-y (x+y)/x /(x-(2xy-y^2)/x) 因式分解 x³-xy²/x³+2x²y+xy² 与x²-y²/x(x+3y)+y(y-x) 急、、、、 代数 x^-y^/ x^-(y-z)^ 除以 x^+2xy+y^/(x-y)^-z^ 乘 x^+xy-xz/x^-xy 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) (x-y)[(x+y)^2-xy]+(x-y)[(x-y)^2+xy] 已知x-xy =21,xy-y=-12,分别求式子x-y与x-2xy +y x根号x+x根号y/xy-y^2)-（x+根号xy+y/x根号x-y根号）y .(x+y-2)(x+y-2xy)+(xy-1)^2 (x^2-xy)y÷y-x/xy怎么做? 设x,y∈R,比较(x*2+y*2)*2与xy(x+y)*2