3x-2y/2=3y-2z/3=3z-2x/4=-2

试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 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 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 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 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 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai x-y+4z=10,x+3y+2z=2,x+2y+3z=11. x+2y+3z=10,x-y+4z=10,x+3y+2z=2 x+y+z=4 2x+3y-z=6 3x+2y+2z=10 已知,x/2=y/3=z/4,则(2x+y-z)/(3x-2y+z)=? x+y+z=2 4x+2y+z=4 2x+3y+z=1