x+2y+4z=17 2x+y+z=7 3x+y+2z=11

x+2y+4z=17 2x+y+z=7 3x+y+2z=11 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, x/2=y/3=z/5 x+3y-z/x-3y+z x+2y+3z=14 2x+y+z=7 3x+y+2z=11 2x-y+2z=-17 3x+y-3z=-4 x+y+z=6 解方程：{2x+3y+z=7,x+y+z=4,3x+y-z=-4 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 2x+5y+4z=0,3x+y-7z=0,则x+y-z=? 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z