| 1500 | ( | 12000 | − | x | ) | = | 1300 | ( | 10000 | − | x | ) |
| 方程左边 = | 1500 | × | 12000 | − | 1500 | x |
| = | 18000000 | − | 1500 | x |
| 18000000 | − | 1500 | x | = | 1300 | ( | 10000 | − | x | ) |
| 方程右边 = | 1300 | × | 10000 | − | 1300 | x |
| = | 13000000 | − | 1300 | x |
| 18000000 | − | 1500 | x | = | 13000000 | − | 1300 | x |
| - | 1500 | x | + | 1300 | x | = | 13000000 | − | 18000000 |
| - | 200 | x | = | 13000000 | − | 18000000 |
| - | 200 | x | = | - | 5000000 |
| 5000000 | = | 200 | x |
| 200 | x | = | 5000000 |
| x | = | 5000000 | ÷ | 200 |
| = | 5000000 | × | 1 200 |
| = | 25000 | × | 1 |
| x | = | 25000 |