3x+2y+z=315 x+2y+3z=285怎么解
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:3x+2y+z=315 x+2y+3z=285
x/2=y/3=z/5 x+3y-z/x-3y+z
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
解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3
解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3
3x-y+z=3 2x+y-3z=11 x+y+z=12 解方程
解方程组:x-2y+z=-1,x+y+z=2,x+2y+3z=-1
解方程组{2x+3y+z=11,x+y+z=0,3x-y+z=-2.
解方程组{3x+y-z=4,2x-y+3z=12,x+y+z=6}
解方程:{2x+3y+z=7,x+y+z=4,3x+y-z=-4
解方程{3x -y+z=4 2x+3y-z=12 x+y+z=6