| 200 | × | 10 100 | + | 20 100 | x | = | 12 100 | ( | 200 | + | x | ) |
| 方程左边 = | 20 | + | 20 100 | x |
| 20 | + | 20 100 | x | = | 12 100 | ( | 200 | + | x | ) |
| 方程右边 = | 12 100 | × | 200 | + | 12 100 | x |
| = | 24 | + | 12 100 | x |
| 20 | + | 20 100 | x | = | 24 | + | 12 100 | x |
20 100 | x | − | 12 100 | x | = | 24 | − | 20 |
2 25 | x | = | 24 | − | 20 |
2 25 | x | = | 4 |
| x | = | 4 | ÷ | 2 25 |
| = | 4 | × | 25 2 |
| = | 2 | × | 25 |
| x | = | 50 |