x+y+z=30 3x+2y+z=50
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
1.x+y+z=30,3x+y-z=50,x,y,z为非负数,求5x+4y+2z取值范围.
x/2=y/3=z/5 x+3y-z/x-3y+z
解方程组x+y+z=30,3x+2y+z=50
x+y+z=30 3x+2y+z=50
(x+y-z)(x-y+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
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
X+Y+Z=?
3道高数题,1,函数F(x,y,z)=(e^x) * y * (z^2) ,其中z=z(x,y)是由x+y+z+xyz=
(x+y-z)^2-(x-y+z)^2=?