31 10 | x | − | 59 10 | ( | x | + | 9 2 | ) | = | 77 10 | x | − | 1959 20 |
| 方程左边 = | 31 10 | x | − | 59 10 | x | − | 59 10 | × | 9 2 |
| = | 31 10 | x | − | 59 10 | x | − | 531 20 |
| = | - | 14 5 | x | − | 531 20 |
| - | 14 5 | x | − | 531 20 | = | 77 10 | x | − | 1959 20 |
| - | 14 5 | x | − | 77 10 | x | = | - | 1959 20 | + | 531 20 |
| - | 21 2 | x | = | - | 1959 20 | + | 531 20 |
| - | 21 2 | x | = | - | 357 5 |
357 5 | = | 21 2 | x |
21 2 | x | = | 357 5 |
| x | = | 357 5 | ÷ | 21 2 |
| = | 357 5 | × | 2 21 |
| = | 17 5 | × | 2 |
| x | = | 34 5 |
| x | = | 6.8 |