已知x+y=3则1/2x^2+xy+1/2y^2=多少

已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 已知x+y=1,xy=-2,则x²y+xy²-2xy 已知1/x=1/y=6,则3x-2xy+3y/3xy+x+y=?已知1/x+1/y=6,则3x-2xy+3y/3xy+x+y=? 已知1/x=3+1/y,则(2x-5xy-2y)/(y+3xy-x)=_______. 已知1/x+1/y=3,则2x-3xy+2y/x+xy+y=谢谢了, 已知1/x-1/y=-3,则x+3xy-y/3x-2xy-3y= 已知1/x-1/y=5,则2x+3xy-2y/y+2xy-x 已知1/x-1/y=-3,则x+5xy-y/3x-2xy-3y= 已知1/X+1/Y=6,则3X-2XY+3y/3XY+X+Y=多少 已知2/X-1/Y=3,则(X-2Y-XY)/(5XY+6Y-3X)=? 已知2/x-1/y=3,则(2y-x+4xy)/(3x-6y-5xy)=? 已知1/x减1/y=-3,则(2x+xy-2y)/x-xy-y的值为 已知1/X-1/Y=5 ,则x-2xy-y/4x+3xy-4y 已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y) .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 已知x(x-1)-(x²-y)=-3,求(x²y+xy²)÷xy-2y 已知x y=1,xy=-3,求2xy-4x 4(y-2(xy-x)) 已知x+y=1,xy=1/5,则x^2y=xy^2