4（√x＋√（y－1）＋√（z－2））＝x＋y＋z＋9
x-4√x+y-1-4√y-1+z-2-4√z-2+12=0
(√x-2)^2+(√y-1-2)^2+(√z-2-2)^2=0
x=4 y=5 z=6
xyz=120