| x | ÷ | 72 | × | 1000 | = | 9 | ( | 5 | + | x | ÷ | 72 | ÷ | 21 20 | ) |
| 方程左边 = | x | × | 125 9 |
125 9 | x | = | 9 | ( | 5 | + | x | ÷ | 72 | ÷ | 21 20 | ) |
| 方程右边 = | 9 | × | 5 | + | 9 | x | ÷ | 72 | ÷ | 21 20 |
| = | 45 | + | 5 42 | x |
125 9 | x | = | 45 | + | 5 42 | x |
125 9 | x | − | 5 42 | x | = | 45 |
1735 126 | x | = | 45 |
| x | = | 45 | ÷ | 1735 126 |
| = | 45 | × | 126 1735 |
| = | 9 | × | 126 347 |
| x | = | 1134 347 |
| x | = | 3.268012 |