x^2+y^2-x^2y^2-4xy-1 分解因式

(x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) .(x+y-2)(x+y-2xy)+(xy-1)^2 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² x-y/x^2+xy除以xy-x^2/x^2y^2-x^4*1/x-y 计算:2xy/(x+y)².(x+y)/4y 化简:[4xy(x-y)^-1 + (xy^-1 - x^-1y)/(x^-1 + y^-1)] / (x+y)^2 x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² (-x-y)(x^2+xy+y^2) 计算:(4xy(x-y)^-1+(x(y^-1)-(x^-1)y)/((x^-1)+(y^-1)))*(x+y)^-2 XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) 1-2/x+y=xy,4y+6x=xy.求xy的解? (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) （x^2+xy/x-y)/（xy/x-y)计算 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) {(x-y/x^2-2xy+y^2)-(xy+y^2/x^2-y^2)}*(xy/y-1)