知x/3=y/4=z/5,求(xy+yz+xz)/xx+yy+zz

知x/3=y/4=z/5,求(xy+yz+xz)/xx+yy+zz 已知XY=2(X+Y),YZ=4(Y+Z),ZX=5(Z+X),求X,Y,Z已知XY=2(X+Y),YZ=4(Y+Z),ZX=5(Z+X),求X,Y,Z 分式题:xy=x+y,yz=2(y+z),zx=3(z+x),求xyz/(xy+yz+xz)xy=x+y,yz=2(y+z),zx=3(z+x),求xyz/(xy+yz+xz) x/3=y/4=z/5 求xy+yz+zx/x^2+y^2+z^2的值 方程组xy/x+y=2 yz/y+z=4 zx/x+z=5 求x,y,z 方程组：(x+y)/xy=3 (y+z)/yz=4 (z+x)/xz=5 X+Y+Z=5,XY+XZ+YZ=3求Z范围 若实数x,y,z满足x+y+z=5,xy+yz+xz=3,求z的最大值 实数x,y,z满足x+y+z=5,xy+yz+zx=3,求z的最大值 时数x,y,z满足x+y+z=5,xy+yz+zx=3,求Z最大值 已知x+y+yz=5,y+z+xy=8,x+z+xy=9,求x,y,z XYZ满足XY/X+Y=-2,YZ/Y+Z=3/4,ZX/Z+X=-4/3,求XYZ/XY+YZ+ZX的值 数学题 xy&x+y =-2,yz&y+z=4&3 zx&z+x=-4&3 求XYZ%xy+xz+yz xy/x+y=6/5 yz/y+z=12/7 xz/x+z=4/3 求x和y和z 已知4x-5y+2z=0,x+4y-3z=0,求(x²+y²+z²)/xy+yz+xz 己知x/2=y/3=z/4,求xy+yz+zx/5x的平方+3y的平方+z的平方的值 x,y,z为实数,且xy/x+y=1/3,yz/y+z=1/4,xz/x+z=1/5,求xyz/xy+yz+zx的值 数学高手解一道分式计算题,一定要写过程x.y.z为实数,且xy/x+y=1/3,yz/y+z=1/4,xz/x+z=1/5,求xyz/xy+yz+zx