若-x^2y=2,则-xy（x^5y^2-x^3y+2x）的值为多少?

若xy/x+y=2,则3x-5xy+3y/-x+3xy-y=?/是分之 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若 x+y=5,xy=-50 则x^2y+xy^2 =( ) 若x-y=1,xy=5,则x^2y-xy^2＝ 若x/1-y/1=5,则x-2xy-y/2x+5xy-2y=? 若1/x+1/y=2,则(2x-xy+2y)÷(3x+5xy+3y) 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 若x+y分之xy=2,则-x+3xy-y分之3x-xy+3y=多少? 若x+y分之xy=2,则-x+3xy-y分之3x-xy+3y=多少? 若xy/x+y=2,则3x-xy+3y/-x+3xy-y= 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 若xy=2（x+y),求 （3x-5xy+3y)÷(-x+3xy-y) 的值 x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? 已知xy/x+y=2,则代数式3x-5y+8y/-x+3xy-y的值 若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( )若x+y=-1,则x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4=( ） 若x^2+xy+y=14,y^2+xy+x=28,求x+y 函数f(xy,x+y)=x^2+xy+y^2,则df(x,y)=?