{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-9z=17{3x+y+15z=18{x+2y+3z=2
4x-5z=17 3x+y+15z=18 x+2y+3z=2
2) 4x-9z=17 3x+y+15z=18 x+2y+3z=2 (3) 2x+4y+3z=9 3x-2y+5z=11
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
(1) 4x-9z=17 3x+y+15z=18 x+2y+3z=2 (2)2x+4y+3z=9 3x-2y+5z=11
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
2x-y+2z=-17 3x+y-3z=-4 x+y+z=6
x+2y+4z=17 2x+y+z=7 3x+y+2z=11
解方程组x-4y+z=-3,2x+y-z=18,x-y-z=7.