| 3 | ( | x | + | 3 | ) | = | - | 2 | ( | x | − | 7 | ) | − | 5 | x |
| 方程左边 = | 3 | x | + | 3 | × | 3 |
| = | 3 | x | + | 9 |
| 3 | x | + | 9 | = | - | 2 | ( | x | − | 7 | ) | − | 5 | x |
| 方程右边 = | - | 2 | x | + | 2 | × | 7 | − | 5 | x |
| = | - | 2 | x | + | 14 | − | 5 | x |
| = | - | 7 | x | + | 14 |
| 3 | x | + | 9 | = | - | 7 | x | + | 14 |
| 3 | x | + | 7 | x | = | 14 | − | 9 |
| 10 | x | = | 14 | − | 9 |
| 10 | x | = | 5 |
| x | = | 5 | ÷ | 10 |
| = | 5 | × | 1 10 |
| = | 1 | × | 1 2 |
| x | = | 1 2 |
| x | = | 0.5 |