x\2=y\3=z\4 x+y+z=18
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
解方程组x-4y+z=-3,2x+y-z=18,x-y-z=7.
已知x:y:z=2:3:4,且x+y+z=18,求x,y,z的值
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
(x+y-z)(x-y+z)=
x/2=y/3=z/5 x+3y-z/x-3y+z
{4x-9z=17 3x+y+15z=18 x+2y+3z=2
4X-9Z=17 3X+Y+15Z=18 X+2Y+3Z=2
{4x-9z=17{3x+y+15z=18{x+2y+3z=2
4x-5z=17 3x+y+15z=18 x+2y+3z=2
x/2=y/3=z/4 3x-5y+3z=18
x/2=y/3=z/4 x+y+z=18 求方程组解