x²=y²+z²+2yz 假如x是7那么这个怎么做要流程

因式分解x²-y²-z²+2yz 因式分解x²-y²-z²=2yz+2x+1 已知x+y+z=1,x²+y²+z²=2求xy+yz+xz的值 已知x+y+z=2,xy+yz+zx=-5,求x²+y²+z²的值 已知x+y+z=1,x²+y²+z²=2求xy+yz+zx x／3=y／2＝z／5,求xy+yz+xz／x²+y²+z² 2x^2 + 2y^2 + z^2 + 8yz − z + 8 = 0,那么z=z(x,y)怎么求? 已知x-y=2+a,y-z=2-a,且a²=7,试求x²+y²+z²-xy-yz 已知2x-y-5z=0,x-2y+2z=0,求x²+y²+z²/xy+yz+zx的值. 已知4x-3y-3z=0,x-3y-z=0 求xy+2yz/x²+y²+z² 已知4x-5y+2z=0,x+4y-3z=0,求(x²+y²+z²)/xy+yz+xz 已知3x-4y-z=0 2x+y-8z =0,求(x²+y²-z²)/(xy+yz)的值