解y+2z=-2;3x+y-4z=1;2x-y+2x=8
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
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,
已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1
解方程组:x-2y+z=-1,x+y+z=2,x+2y+3z=-1
x+y+z=2 4x+2y+z=4 2x+3y+z=1
解方程:{2x+3y+z=7,x+y+z=4,3x+y-z=-4
解三元一次方程:x+y-z=0,2x+y+z=7,x-3y+z=8
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