3x+2y+z=13 x+y+2z=7 2x+3y-z=12 x=?y=?z=?
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
x/2=y/3=z/5 x+3y-z/x-3y+z
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
1.x+y+z=21,x-y=1,2x+z-y=13.2.3x+2y+z=13,x+y+2z=7 ,2z+3y-z=12
3x+2y+z=13 x+y+2z=7 2x+3y-z=12 x=?y=?z=?
{3x+2y+z=13 x+y+2z=7 2x+3y-z=12,求x,y,z
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
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=1;x+3y+7z=-1;z+5y+8z=-2
(x+y-z)(x-y+z)=
(x+y-z)^2-(x-y+z)^2=?
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