- 已知:"3X-4-Z=0,2X+Y-8Z=0",且,求X*X+Y?
- 已知:"3X-4-Z=0,2X+Y-8Z=0",且,求X*X+Y*Y+Z*Z/XY+YZ+2XZ的值 修改
- 已知:"3x-4y-z=0,2x+y-8z=0"求(x^2+y^2+z^2)/(xy+yz+2xz)的值
解:
由
3x-4y-z=0
2x+y-8z=0
解得:
x=3z
y=2z
则
(x^2+y^2+z^2)/(xy+yz+2xz)
=(9z^2+4z^2+z^2)/(6z^2+2z^2+6z^2)
=(9+4+1)/(6+2+6)
=14/14
=1