| 8 | ( | x | + | 3 | ) | − | 3 | ( | - | x | − | 5 | ) | = | 7 | ( | x | + | 5 | ) | − | 16 |
| 方程左边 = | 8 | x | + | 8 | × | 3 | − | 3 | ( | - | x | − | 5 | ) |
| = | 8 | x | + | 24 | − | 3 | ( | - | x | − | 5 | ) |
| = | 8 | x | + | 24 | + | 3 | x | + | 3 | × | 5 |
| = | 8 | x | + | 24 | + | 3 | x | + | 15 |
| = | 11 | x | + | 39 |
| 11 | x | + | 39 | = | 7 | ( | x | + | 5 | ) | − | 16 |
| 方程右边 = | 7 | x | + | 7 | × | 5 | − | 16 |
| = | 7 | x | + | 35 | − | 16 |
| = | 7 | x | + | 19 |
| 11 | x | + | 39 | = | 7 | x | + | 19 |
| 11 | x | − | 7 | x | = | 19 | − | 39 |
| 4 | x | = | 19 | − | 39 |
| 4 | x | = | - | 20 |
| x | = | - | 20 | ÷ | 4 |
| = | - | 20 | × | 1 4 |
| = | - | 5 | × | 1 |
| x | = | - | 5 |