设3/x=5/y=7/z,则3y-2z/y+3z=什么?
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
x/2=y/3=z/5 x+3y-z/x-3y+z
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
设X+Y+Z=0求X^3+X^2Z-XYZ+Y^2Z+Y^3的值
设x+y+z=11求函数u=2x*x+3y*y+z*z的最小值
16.设x+y+z=3y=2z ,求x/(x+y+z)的值5.7
若3x+7y+z=5,4x+10y+z=3,则x+y+z=?
若x/3=y/2=z/5,则2x-3y-z/x-y+z=
2x+5y+4z=6,3x+y-7z=-4,x+y-z=?
已知2x+5y+4z=15.7x+y+3z=14 则x+y+z=?
已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z