不难,初中生吧?
设 y1=k1/x
y2=k2(x-2)
x=1时
y=y1-y2=k1+k2=-1
x=3时
y=y1-y2=k1/3-k2
解得,k1=3,k2=-4;
故有
y=3/x+4x+8