1.已知x-y=xy,则1/x-1/y=2.若1/a:1/b:1/c=2:3:4,则a:b:c=3.已知A、B两地相距s千米.王强骑摩托车从A地往B地需m小时;赵瑞骑自行车从B地往A地需n小时,则王强骑摩托车的速度是赵瑞骑自行车的多少倍?

已知x+y=1,xy=-2,则x²y+xy²-2xy 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= 已知,x、y是非零数,xy/x+y=5.则1/x+1/y=? 已知x+y=1,x>0,y>0,则2x+y/xy等于 已知x+y=1,xy=1/5,则x^2y=xy^2 已知x+y=3,xy=1,则4x+3xy+4y= 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+1/y=2,则(x+y+2xy+2y^2)/(2xy+y^2)=? 已知1/x-1/y=3,则(5x+xy-5y)/(x-xy-y) =9= 已知1/X-1/Y=3 则(5X+XY-5Y)/(X-XY-Y)=? 已知1/x=3+1/y,则(2x-5xy-2y)/(y+3xy-x)=_______. 已知1/x-1/y=-3,则x+5xy-y/3x-2xy-3y= 已知1/x-1/y=-3,则x+3xy-y/3x-2xy-3y= 已知1/X+1/Y=6,则3X-2XY+3y/3XY+X+Y=多少 已知1/x+1/y=3,则2x-3xy+2y/x+xy+y=谢谢了, 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-1/y=3,则5x+xy-5y/x-xy-y等于