5x+2y-4z=1,3x-3y+2z=1,-2x+3y-2z= 0

{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) x/2=y/3=z/5 x+3y-z/x-3y+z x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=- {x+y+z=4 {2y+z=0 {3x+2y-4z=-1 若x-2y+4z=1,x+3y-7z=0,则y:z=? 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/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= 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 2x-2y+z=0 2x+y-z=1 x+3y-2z=1