| 10000 | ( | 9 500 | + | 21 500 | ) | = | 12500 | ( | 9 500 | + | x | ) |
| 方程左边 = | 10000 | × | 9 500 | + | 10000 | × | 21 500 |
| = | 180 | + | 420 |
| = | 600 |
| 600 | = | 12500 | ( | 9 500 | + | x | ) |
| 方程右边 = | 12500 | × | 9 500 | + | 12500 | x |
| = | 225 | + | 12500 | x |
| 600 | = | 225 | + | 12500 | x |
| - | 12500 | x | = | 225 | − | 600 |
| - | 12500 | x | = | - | 375 |
| 375 | = | 12500 | x |
| 12500 | x | = | 375 |
| x | = | 375 | ÷ | 12500 |
| = | 375 | × | 1 12500 |
| = | 3 | × | 1 100 |
| x | = | 3 100 |
| x | = | 0.03 |