| ( | 15 | ( | 1 | + | 20 100 | ) | ) | + | ( | 3 100 | x | ) | = | x |
| 方程左边 = | 15 | ( | 1 | + | 20 100 | ) | + | ( | 3 100 | x | ) |
| = | 15 | × | 1 | + | 15 | × | 20 100 | + | ( | 3 100 | x | ) |
| = | 15 | + | 3 | + | ( | 3 100 | x | ) |
| = | 18 | + | ( | 3 100 | x | ) |
| = | 18 | + | 3 100 | x |
| 18 | + | 3 100 | x | = | x |
3 100 | x | − | x | = | - | 18 |
| - | 97 100 | x | = | - | 18 |
| 18 | = | 97 100 | x |
97 100 | x | = | 18 |
| x | = | 18 | ÷ | 97 100 |
| = | 18 | × | 100 97 |
| x | = | 1800 97 |
| x | = | 18.556701 |