已知4x-3y-6z=0,2x+4y-14z=0,求2x²+3y²+6z²/x²+5y²+7z

已知4x-3y-6z=0,2x+4y-14z=0,求2x²+3y²+6z²/x²+5y²+7z
已知4x-3y-6z=0,2x+4y-14z=0,求2x²+3y²+6z²/x²+5y²+7z

已知4x-3y-6z=0,2x+4y-14z=0,求2x²+3y²+6z²/x²+5y²+7z
缺少条件：x,y,z均不等于0,而且分式中应为7z².
4x-3y-6z=0 (1)
2x+4y-14z=0 (2)
(2)×2-(1)
11y-22z=0
y=2z
代入(1)
4x-6z-6z=0
x=3z
x=3z,y=2z代入(2x²+3y²+6z²)/(x²+5y²+7z²)
(2x²+3y²+6z²)/(x²+5y²+7z²)
=(18+12+6)z²/[(9+20+7)z²]
=36/36
=1