| xy |
| x+y |
| xz |
| x+z |
| yz |
| y+z |
∴
| x+y |
| xy |
| 1 |
| a |
| x+z |
| xz |
| 1 |
| b |
| y+z |
| yz |
| 1 |
| c |
∴
| 1 |
| a |
| 1 |
| x |
| 1 |
| y |
| 1 |
| b |
| 1 |
| x |
| 1 |
| z |
| 1 |
| c |
| 1 |
| y |
| 1 |
| z |
①+②-③得
| 1 |
| a |
| 1 |
| b |
| 1 |
| c |
| 2 |
| x |
∴x=
| 2abc |
| bc+ac−ab |
| xy |
| x+y |
| xz |
| x+z |
| yz |
| y+z |
| xy |
| x+y |
| xz |
| x+z |
| yz |
| y+z |
| x+y |
| xy |
| 1 |
| a |
| x+z |
| xz |
| 1 |
| b |
| y+z |
| yz |
| 1 |
| c |
| 1 |
| a |
| 1 |
| x |
| 1 |
| y |
| 1 |
| b |
| 1 |
| x |
| 1 |
| z |
| 1 |
| c |
| 1 |
| y |
| 1 |
| z |
| 1 |
| a |
| 1 |
| b |
| 1 |
| c |
| 2 |
| x |
| 2abc |
| bc+ac−ab |