2x+3y+z=0 3x+y-4z=11 x+y+z=-3
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3
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
若{x+3y+10z=0 则 (x+y-z)/(x-y+z)
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
3x+2y+z=9,x+y+2z=0,2x+3y-z=11
解方程组{2x+3y+z=11,x+y+z=0,3x-y+z=-2.
x-3y+z=0,3x-2y-4z=0,则x:y:z=多少?
已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=?
x+2y+4z=17 2x+y+z=7 3x+y+2z=11
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?