x+y=x+2y-3=z 2x-3y+2z=5
x/2=y/3=z/5 x+3y-z/x-3y+z
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
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
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y-
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
x+y=z 2x-3y+2z=5 x+2y-z=3
解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3
x+y-z=0 2x-3y+2z=5 x+2y-z=3
解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3