| 1 | − | 5 | ( | x | + | 1 | ) | = | 7 | ( | x | − | 1 | ) |
| 方程左边 = | 1 | − | 5 | x | − | 5 | × | 1 |
| = | 1 | − | 5 | x | − | 5 |
| = | - | 4 | − | 5 | x |
| - | 4 | − | 5 | x | = | 7 | ( | x | − | 1 | ) |
| 方程右边 = | 7 | x | − | 7 | × | 1 |
| = | 7 | x | − | 7 |
| - | 4 | − | 5 | x | = | 7 | x | − | 7 |
| - | 5 | x | − | 7 | x | = | - | 7 | + | 4 |
| - | 12 | x | = | - | 7 | + | 4 |
| - | 12 | x | = | - | 3 |
| 3 | = | 12 | x |
| 12 | x | = | 3 |
| x | = | 3 | ÷ | 12 |
| = | 3 | × | 1 12 |
| = | 1 | × | 1 4 |
| x | = | 1 4 |
| x | = | 0.25 |