3式-2式:x-y=1
3式:x²+z=9即(x+3)(x-3)=z
1式:2(x-3)/(x-1)=z
则(x+3)(x-1)=2,解得:x=±(根号6)-1,y=±(根号6)-2,z=±2(根号6)-2,一一对应.