已知xyz=1,x+y+z=2,x2+y2+z2=16?求[1÷(xy+2z)+1÷(yz+2x)+1÷(zx+2y)]
已知xyz=1,x+y+z=2,x2+y2+z2=16?求[1÷(xy+2z)+1÷(yz+2x)+1÷(zx+2y)]
已知x,y,z互不相等,且xyz不等于0,x2+yz=z2,y2+zx=x2,求证:z2+xy=y2
已知xyz=1,x+y+z=2,x2+y2+z2=16,求代数式1xy+2z+1yz+2x+1zx+2y
已知x+y+z=1,x2+y2+z2=2,x3+y3+z3=3,求xy(x+y)+yz(y+z)+zx(z+x)的值
已知x+y+z=1,xy+yz+zx=2,xyz2,求x2(y+z)+y2(z+x)+z2(x+y)的值
已知xy/x+y=1,yz/y+z=2,zx/z+x=3,求x的值
急已知三个数x y z满足xy/(x+y)=-2,yz/(y+z)=4/3,zx/(z+x)=-4/3,则xyz/(xy
实数x,y,z,若x2+y2=1,y2+z2=2,z2+x2=2,则xy+yz+zx的最小值是 怎求
已知x、y、z都是实数,且x2+y2+z2=1,则m=xy+yz+zx( )
xy/x+y=1,yz/y+z=2,xz/x+z=3求x,y
已知x+y-z=0,2x-y-8z=0,且xyz不等于0,则x2+y2+z2/(xy+yz+zx)等于
附加题:(1)已知x-y=2+a,y-z=2-a,且a2=7,试求x2+y2+z2-xy-yz-zx的值.(2)已知对多