由y+1/z=1,得1/z=1-yz=1/(1-y)=(1-y+y)/(1-y)=1+y/(1-y)将其代入z+1/x=1,得1+y/(1-y)+1/x=1则：y/(y-1)=1/x则：x=(y-1)/y=1-1/y,即：x+1/y=1
