-(2xy-y^2+1/2x^2)-2(1/3xy+1/4y^2-x^2)

.(x+y-2)(x+y-2xy)+(xy-1)^2 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) x^2-xy/xy-y^2约分 计算3xy[2xy-x(y-2)+x-1] {(x-y/x^2-2xy+y^2)-(xy+y^2/x^2-y^2)}*(xy/y-1) （x^2+xy/x-y)/（xy/x-y)计算 1.（xy-1）^2-(x+y-2xy)(2-x-y)2.(x+y)(x+y+2xy)+(xy-1)(xy+1) (-1/3xy)^2•[xy(2x-y)-2x(xy-y^2)] xy(xy+1)+xy+3-2(x+y+1/2)-(x+y-1)^2因式分解 (-3分之1xy)的平方×[xy(2x-y)-2x(xy-y的平方)] 已知x+y=1,xy=-2,则x²y+xy²-2xy 因式分解（x+y)(x+y+2xy)+(xy+1)(xy-1) 分解因式(x+y)(x+y+2xy)+(xy+1)(xy-1) 分解因式：(X+Y）*（X+Y+2XY）+（XY+1）*（XY-1） 1-2/x+y=xy,4y+6x=xy.求xy的解? XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y (-x-y)(x^2+xy+y^2)