x^2-y^2/x^2+2xy+y^2-x+y/x-y,其中x=1,y=-3带数求值!^-^下列运算正确的是 （ ）A.a/a-b-b/b-a=1 B.m/a-n/b=m-n/a-bC.b/a-b+1/a=1/a D.2/a-b-a+b/a^2-b^2=1/a-b

(-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 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? 代数 x^-y^/ x^-(y-z)^ 除以 x^+2xy+y^/(x-y)^-z^ 乘 x^+xy-xz/x^-xy (x+y)/x /(x-(2xy-y^2)/x) 因式分解 x^2-xy/xy-y^2约分 （y/(x^2-xy)+x/(y^2-xy))除以(x-y)/(xy) (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) x^2y-2xy+y化简 X^Y-2XY^2+y^3 x-y/xy-y^2计算