| ( | 89 | ( | 1 | + | 15 100 | ) | ) | + | ( | 8 100 | x | ) | = | x |
| 方程左边 = | 89 | ( | 1 | + | 15 100 | ) | + | ( | 8 100 | x | ) |
| = | 89 | × | 1 | + | 89 | × | 15 100 | + | ( | 8 100 | x | ) |
| = | 89 | + | 267 20 | + | ( | 8 100 | x | ) |
| = | 2047 20 | + | ( | 8 100 | x | ) |
| = | 2047 20 | + | 8 100 | x |
2047 20 | + | 8 100 | x | = | x |
8 100 | x | − | x | = | - | 2047 20 |
| - | 23 25 | x | = | - | 2047 20 |
2047 20 | = | 23 25 | x |
23 25 | x | = | 2047 20 |
| x | = | 2047 20 | ÷ | 23 25 |
| = | 2047 20 | × | 25 23 |
| = | 89 4 | × | 5 |
| x | = | 445 4 |
| x | = | 111.25 |