| 120 | ÷ | x | − | 20 | = | ( | 120 | − | 1 2 | x | ) | ÷ | 3 2 | ÷ | x |
| 方程两边同时乘以: | x |
| 120 | − | 20 | x | = | ( | 120 | − | 1 2 | x | ) | ÷ | 3 2 | ÷ | 1 | × | 1 |
| 120 | − | 20 | x | = | 120 | ÷ | 3 2 | ÷ | 1 | × | 1 | − | 1 2 | x | ÷ | 3 2 | ÷ | 1 | × | 1 |
| 120 | − | 20 | x | = | 80 | − | 1 3 | x |
| - | 20 | x | + | 1 3 | x | = | 80 | − | 120 |
| - | 59 3 | x | = | 80 | − | 120 |
| - | 59 3 | x | = | - | 40 |
| 40 | = | 59 3 | x |
59 3 | x | = | 40 |
| x | = | 40 | ÷ | 59 3 |
| = | 40 | × | 3 59 |
| x | = | 120 59 |
| x | = | 2.033898 |