| ( | 140 | − | x | ) | − | 7 | = | ( | 1 | − | 1 | ÷ | 4 | ) | x |
| 方程左边 = | 140 | − | x | − | 7 |
| = | 133 | − | x |
| 133 | − | x | = | ( | 1 | − | 1 | ÷ | 4 | ) | x |
| 方程右边 = | 1 | x | − | 1 | ÷ | 4 | × | x |
| = | 1 | x | − | 1 4 | x |
| = | 3 4 | x |
| 133 | − | x | = | 3 4 | x |
| - | x | − | 3 4 | x | = | - | 133 |
| - | 7 4 | x | = | - | 133 |
| 133 | = | 7 4 | x |
7 4 | x | = | 133 |
| x | = | 133 | ÷ | 7 4 |
| = | 133 | × | 4 7 |
| = | 19 | × | 4 |
| x | = | 76 |