（x^2+y^2）/（x^2-xy+y^2）=2,求x/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 (xy-x²)÷(x²-2xy+y²/xy)×（x-y/x²） x-y/x²÷x²-2xy+y²/xy*（xy-x²） (-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/x+y）^2÷（y-x/x^2+2xy+y^2)^2 X-Y/2X+2Y XY/X+Y² 因式分解：x×x-xy-2y×y-x-y 计算：3xy[2xy-x（y-2）+x] 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] .(x+y-2)(x+y-2xy)+(xy-1)^2 (x^2-xy)y÷y-x/xy怎么做? 2（x+y）等于2xy/（x+y)为什么? 1.（xy-1）^2-(x+y-2xy)(2-x-y)2.(x+y)(x+y+2xy)+(xy-1)(xy+1) 【（x+y）²-（x-y）²】/2xy