| ( | ( | x | − | 4 | ) | ÷ | 1 5 | ) | − | 5 2 | = | ( | x | − | 3 | ) | ÷ | 1 20 |
| 方程左边 = | ( | x | − | 4 | ) | ÷ | 1 5 | − | 5 2 |
| = | x | × | 5 | − | 4 | × | 5 | − | 5 2 |
| = | x | × | 5 | − | 20 | − | 5 2 |
| = | 5 | x | − | 45 2 |
| 5 | x | − | 45 2 | = | ( | x | − | 3 | ) | ÷ | 1 20 |
| 方程右边 = | x | × | 20 | − | 3 | × | 20 |
| = | x | × | 20 | − | 60 |
| 5 | x | − | 45 2 | = | 20 | x | − | 60 |
| 5 | x | − | 20 | x | = | - | 60 | + | 45 2 |
| - | 15 | x | = | - | 60 | + | 45 2 |
| - | 15 | x | = | - | 75 2 |
75 2 | = | 15 | x |
| 15 | x | = | 75 2 |
| x | = | 75 2 | ÷ | 15 |
| = | 75 2 | × | 1 15 |
| = | 5 2 | × | 1 |
| x | = | 5 2 |
| x | = | 2.5 |