| 100000 | = | 2000 | x | − | ( | 30000 | + | 140 | x | ) |
| 方程右边 = | 2000 | x | − | 30000 | − | 140 | x |
| = | 1860 | x | − | 30000 |
| 100000 | = | 1860 | x | − | 30000 |
| - | 1860 | x | = | - | 30000 | − | 100000 |
| - | 1860 | x | = | - | 130000 |
| 130000 | = | 1860 | x |
| 1860 | x | = | 130000 |
| x | = | 130000 | ÷ | 1860 |
| = | 130000 | × | 1 1860 |
| = | 6500 | × | 1 93 |
| x | = | 6500 93 |
| x | = | 69.892473 |