| ( | 601 20 | − | x | ) | ÷ | 2 | = | 19 500 |
| 方程左边 = | 601 20 | × | 1 2 | − | x | × | 1 2 |
| = | 601 40 | − | x | × | 1 2 |
601 40 | − | 1 2 | x | = | 19 500 |
| - | 1 2 | x | = | 19 500 | − | 601 40 |
| - | 1 2 | x | = | - | 14987 1000 |
14987 1000 | = | 1 2 | x |
1 2 | x | = | 14987 1000 |
| x | = | 14987 1000 | ÷ | 1 2 |
| = | 14987 1000 | × | 2 |
| = | 14987 500 | × | 1 |
| x | = | 14987 500 |
| x | = | 29.974 |