| 3 | x | − | 180 | ÷ | 4 | × | x | − | 180 | = | 9 | ÷ | 13 |
| 方程左边 = | 3 | x | − | 45 | x | − | 180 |
| = | - | 42 | x | − | 180 |
| - | 42 | x | − | 180 | = | 9 | ÷ | 13 |
| 方程右边 = | 9 13 |
| - | 42 | x | − | 180 | = | 9 13 |
| - | 42 | x | = | 9 13 | + | 180 |
| - | 42 | x | = | 2349 13 |
| - | 2349 13 | = | 42 | x |
| 42 | x | = | - | 2349 13 |
| x | = | - | 2349 13 | ÷ | 42 |
| = | - | 2349 13 | × | 1 42 |
| = | - | 783 13 | × | 1 14 |
| x | = | - | 783 182 |
| x | = | - 4.302198 |