若x^2-xy=3,y^2+xy=5,那么x^2+y^2=------,2x^2+xy+3y^2=------,2x^2-5xy-3y^2=------

若xy/x+y=2,则3x-5xy+3y/-x+3xy-y=?/是分之 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 若xy=2（x+y),求 （3x-5xy+3y)÷(-x+3xy-y) 的值 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= 2xy+5y^2+( )=x^2+3xy 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值. 已知xy^2=-2 求-xy(x^2y^5-xy^3-y) 已知xy^2=-2xy(x^2y^5-xy^3-y) xy^2=-3,求-xy(x^2y^5-xy^3-y) 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 若(y-x)/xy=3,求分式(2x+3xy-2y)/(x-2xy-y)的值 若y-x/xy=3,求分式2x+3xy-2y/x-2xy-y 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x+y分之xy=2,那么3x-5xy+3y分之3xy-x-y= 如果xy/x+y=2,那么3x-5xy+3y/-x+3xy-y=?