x>0,y>0,z>0,x^2+xy+y^2=49,y^2+yz+z^2+36,z^2+xz+x^2=25,求x+y+z

(2X+Z-Y)/(X^2-XY+XZ-YZ)-(Y-Z)/(X^2-XY-XZ+YZ) 已知x+y+z=1,xy+yz+xz=0,求x^2+y^2+z^2的值. 已知x^2+y^2+z^2-xy-yz-xz=0,求x,y,z 的大小关系 x+3y+7z=0 2x+5y+11z=0,求(x^2+y^2+z^2)/(xy+2yz+3xz) 1.已知3x-4y-z=0,2x+y-8z=0.求x²+y²+z²/xy+yz+2xz 的 已知4x-5y+2z=0,x+4y-3z=0,求(x²+y²+z²)/xy+yz+xz 求(2X+Z-Y)/(X^2-XY+XZ-YZ)-(2X+Y+Z)/(X^2+XY+XZ+YZ) 已知x>0,y>0,z>0,证明x^3/(x+y)+y^3/(y+z)+z^3/(z+x)≥(xy+xz+yz)/2 x^2+y^2+xy=25/4,x^2+z^2+xz=169/4,y^2+z^2+yz=36,求xy+xz+yz 若x,y,z>0 则根号(x^2+y^2+xy)+根号(y^2+z^2=yz)>根号(x^2+z^2+xz) 化简(2x-y-z/x^2-xy-xz+yz)+(2y-x-z/y^2-xy-yz+xz)+(2x-x-y/z^2-xz 若x+y+z=0且x,y,z互不相等.求x^2/(2x^2+yz)+y^2/(2y^+xz)+z^2/(2z^2+xy)