p+b+r=9,p/(x^2-yz)=b/(y^2-yz)=r/(z^2-xy),求(px+by+rz)/(x+y+z)
设x,y,z∈R+,xy+yz+xz=1,证明不等式:(xy)^2/z+(xz)^2/y+(yz)^2/x+6xyz≥x
已知三个数x,y,z,满足xy/x+y=-2,yz/y+z=4/3,zx/z+x=-4/3,求(xyz)/(xy+yz+
已知X+Y+Z=a,XY+YZ+XZ=b,求X*X+Y*Y+Z*Z的值
已知a,b,c,x,y,z都是正数,求(b c)/ax^2 (c a)/by^2 (a b)/cz^2>=2(xy yz
已知xy:yz:zx=3:2:1,求①x:y:z ②x/yz:y/zx
若|x-3|+|y+z|+|2z+1|=0,求xy-yz的值
已知x+y+z=5,xy+yz+zx=9,求x^2+y^2+z^2的值
已知xy/x+y=3,yz/y+z=2,zx/z+x=1,求y的值
x^2+y^2+xy=25/4,x^2+z^2+xz=169/4,y^2+z^2+yz=36,求xy+xz+yz
已知p+q+r=9,且px2−yz=qy2−zx=rz2−xy,则px+qy+rzx+y+z等于( )
XYZ满足XY/X+Y=-2,YZ/Y+Z=3/4,ZX/Z+X=-4/3,求XYZ/XY+YZ+ZX的值
分式题:xy=x+y,yz=2(y+z),zx=3(z+x),求xyz/(xy+yz+xz)