2x+3y+2z=12 3x+4y+z=11 4x+5y+z=12

x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 解下列方程组（1）3x-y+z=3 2x+y-3z=11 x+y+z=12（2）5x-4y+4z=13 2x+7y-3z 1.x+y=16,y+z=12,z+x=102.3x-y+z=4,2x+3y-z=12,x+y+z=63.x+y+z=6 解方程组{3x+y-z=4,2x-y+3z=12,x+y+z=6} 解方程{3x -y+z=4 2x+3y-z=12 x+y+z=6 x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? 已知x+y/2=y+z/3=z+x/4,且x+2y+z=12,求x-2y+z的值 ①x+y+z=6 3x-y+2z=12 x-y-3z=-4 ②x+y-z=2 4x-2y+3y+8=0 x+3y-2z- x/2=y/3=z/5 x+3y-z/x-3y+z 解方程组1、4x+9y=12,3y-2z=1,2x+6z=32、3x-y+2z=3,2x+y-3z=11,x+y+z=1 1,{2x+y+z=-26,x+2y+z=-30,x+y+2z=-28 2,{5x+2y+z=12,4x+3y+z=13 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)