解析:设y1=k1x,y2=k2/(x-2)
∴y=y1-y2=k1x-k2/(x-2),
∵当x=1时,y=1,当x=3时,y=5,
∴k1+k2=1
k1-k2=5
解之,k1=3,k2=-2
∴y=3x+2/(x-2)