| ( | 115 | ( | 1 | + | 20 100 | ) | ) | + | ( | 5 100 | x | ) | = | x |
| 方程左边 = | 115 | ( | 1 | + | 20 100 | ) | + | ( | 5 100 | x | ) |
| = | 115 | × | 1 | + | 115 | × | 20 100 | + | ( | 5 100 | x | ) |
| = | 115 | + | 23 | + | ( | 5 100 | x | ) |
| = | 138 | + | ( | 5 100 | x | ) |
| = | 138 | + | 5 100 | x |
| 138 | + | 5 100 | x | = | x |
5 100 | x | − | x | = | - | 138 |
| - | 19 20 | x | = | - | 138 |
| 138 | = | 19 20 | x |
19 20 | x | = | 138 |
| x | = | 138 | ÷ | 19 20 |
| = | 138 | × | 20 19 |
| x | = | 2760 19 |
| x | = | 145.263158 |