xy=50 x+2y=35 x

xy=50 x+2y=35 x |x|/x+y/|y|+xy/|xy|= 已知：x(x-50y)+xy=50y^2,求：(x-y):y=? （-3x^y+2xy)-( )=4x^+xy (XY-X^2)除以X-Y/XY=? x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? 若 x+y=5,xy=-50 则x^2y+xy^2 =( ) f(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂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 x^2+xy+x=36,y^2+xy+y=20,求x+y. 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)=? f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=? 如果x^2+xy+y-14,y^@+xy+x=28,求x+y的值. f(xy,x-y)=x^2-xy+y^2.求f(x,y) 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? 已知x+y=1,xy=-2,则x²y+xy²-2xy [-xy^2(2x+y)-8xy)-x^2y)]除以2xy=计算