xy/x+y=12,xz/x+z=15,yz/y+z=20,求x,y,z,的值
xy/x+y=12,xz/x+z=15,yz/y+z=20,求x,y,z,的值
已知X+Y+Z=a,XY+YZ+XZ=b,求X*X+Y*Y+Z*Z的值
若x/3=y=z/4,且xy+xz+yz=76,求2x*x+12y*y+9z*z的值
若实数x,y,z满足x+y+z=5,xy+yz+xz=3,求z的最大值
已知x+y+z=1,x²+y²+z²=2求xy+yz+xz的值
x-3=y-2=z-1,求x^2+y^2+z^2-xy-yz-xz的值
已知x+y+z=1,xy+yz+xz=0,求x^2+y^2+z^2的值.
已知x+y+z=10,xy+xz+yz=8,求x方+y方+z方的值
已知x+y+z=10,xy+xz+yz=8,求x²+y²+z²的值
已知xyz=1,求x/(xy+x+1)+y/(yz+y+1)+z/(xz+z+1)的值
已知x:y:z=3:4:6,求xy+yz+xz / x^+y^+z^ 的值?
x+y+z=5,xy+xz+yz=1 ,求Z的最小值和最大值