x^2y^2-xy-72

x^2-xy/xy-y^2约分 （x^2+xy/x-y)/（xy/x-y)计算 x^2y^2-xy-72 (-x-y)(x^2+xy+y^2) 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) .(x+y-2)(x+y-2xy)+(xy-1)^2 (x^2-xy)y÷y-x/xy怎么做? 2x²y-3(2xy-xy)-xy (x^2+2xy+y^2-4xy)*(x^2-2xy+y^2+4xy) （y/(x^2-xy)+x/(y^2-xy))除以(x-y)/(xy) (xy-x²)÷(x²-2xy+y²/xy)×（x-y/x²） x-y/x²÷x²-2xy+y²/xy*（xy-x²） 初二数学化简分式x^2 -y^2/xy - xy-y^2/xy-x^2x^2 -y^2/xy - xy-y^2/xy-x^2 代数 x^-y^/ x^-(y-z)^ 除以 x^+2xy+y^/(x-y)^-z^ 乘 x^+xy-xz/x^-xy x^2-xy-6y^2+3xy+y+2 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]