| x | − | 5 200 | x | − | 1 100 | ( | x | − | 5 200 | x | ) | = | 216 |
| 方程左边 = | 39 40 | x | − | 1 100 | ( | x | − | 5 200 | x | ) |
39 40 | x | − | 1 100 | ( | x | − | 5 200 | x | ) | = | 216 |
| 方程左边 = | 39 40 | x | − | 1 100 | x | + | 1 100 | × | 5 200 | x |
| = | 39 40 | x | − | 1 100 | x | + | 1 4000 | x |
| = | 3861 4000 | x |
3861 4000 | x | = | 216 |
| x | = | 216 | ÷ | 3861 4000 |
| = | 216 | × | 4000 3861 |
| = | 8 | × | 4000 143 |
| x | = | 32000 143 |
| x | = | 223.776224 |