| ( | 69 | ( | 1 | + | 20 100 | ) | ) | + | ( | 5 100 | x | ) | = | x |
| 方程左边 = | 69 | ( | 1 | + | 20 100 | ) | + | ( | 5 100 | x | ) |
| = | 69 | × | 1 | + | 69 | × | 20 100 | + | ( | 5 100 | x | ) |
| = | 69 | + | 69 5 | + | ( | 5 100 | x | ) |
| = | 414 5 | + | ( | 5 100 | x | ) |
| = | 414 5 | + | 5 100 | x |
414 5 | + | 5 100 | x | = | x |
5 100 | x | − | x | = | - | 414 5 |
| - | 19 20 | x | = | - | 414 5 |
414 5 | = | 19 20 | x |
19 20 | x | = | 414 5 |
| x | = | 414 5 | ÷ | 19 20 |
| = | 414 5 | × | 20 19 |
| = | 414 | × | 4 19 |
| x | = | 1656 19 |
| x | = | 87.157895 |