由根号x+根号y-1+根号z-2=1/2(x+y+z)得,2根号x+2根号y-1+2根号z-2=x+y+z=x+1+y-1+1+z-2+1,x-2根号x+1+y-1+2根号y-1+1+z-2+2根号z-2+1=(根号x -1)^2+(根号y-1 -1)^2+(根号z-2 -1)^2=0因为（根号x -1)^2>=0(根号y-1 -1...