5xy^2-(3xy^2-(4xy^2-2x^2y))+2x^2y-xy^2

（xy-x^2)乘以(xy)/(x-y) x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 5xy^2-[3xy^2-(4xy^2-2x^y)]+x^2y-xy^2如何化简 （-3x^y+2xy)-( )=4x^+xy -3(xy-2x²)-[y²-(5xy-4x²)+2xy] (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) 已知x-y=4xy，则2x+3xy-2yx-2xy-y 先化简,再求值 ⒈2(Xy+Xy)-3(Xy-xy)-4Xy,其中X=1,y=-1 5x^2y/-1/2xy*3xy^2 （x^2+xy/x-y)/（xy/x-y)计算 x^2-xy-6y^2+3xy+y+2 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2