若X,Y满足3(XX+YY+ZZ)=(X+Y+Z)(X+Y+Z),则X=Y=Z.请说明理由.
已知14(XX+YY+ZZ)=(X+2Y+3Z)^2,求X:Y:Z
向量内积问题为什么a(x,y,z)、b(x',y',z')的内积a·b=(xx',yy',zz')=xx'+yy'+zz
知x/3=y/4=z/5,求(xy+yz+xz)/xx+yy+zz
若x/3=y/4=z/5,则(xy+yz=xz)/(xx+yy+zz)的值为
已知x=1/2 y=1/3 z=1/4 则(xx+yy-zz+2xy)/(xx-yy+zz-2xz) 得多少?
x+y+z=5,xx+yy+zz=6,求xy-xz-yz的解
已知x-y=5,y-z=4,求xx+yy+zz-xy-yz-xz的值
x分之y+z=y分之z+x=z分之x+y(x+y+z不等于0),求x+y+z分之x+y-z
设x.y.z满足3x=4y=6z(x.y.z都是指数)求证
已知有理数x、y、z两两不等,则x−yy−z,y−zz−x,z−xx−y中负数的个数是( )
设x.y.z满足3x=4y=6z(x.y.z都是指数)比较3x.4y.6z的大小
已知X+Y+Z=1,且XY+YZ+XZ=0,求XX+YY+ZZ的值?