x-y-Z=2 ①y-z-x=-5② Z-x-y=4③①+②得x-y-z+y-z-x＝2-5-2z＝-3z＝1.5②+③得y-z-x+z-x-y＝-5+4-2x＝-1x＝0.5z＝1.5 x＝0.5代入①得0.5-y-1.5＝2-y-1＝2-y＝2+1-y＝3y＝-3
①式＋②式，得：-2z=-3; z=1.5②式+③式，得：-2x=-1；x=0.5代入①式，y=-3
