| 3 | x | − | 4 | ( | x | + | 1 | ) | = | 6 | − | 2 | ( | 2 | x | − | 5 | ) |
| 方程左边 = | 3 | x | − | 4 | x | − | 4 | × | 1 |
| = | 3 | x | − | 4 | x | − | 4 |
| = | - | 1 | x | − | 4 |
| - | 1 | x | − | 4 | = | 6 | − | 2 | ( | 2 | x | − | 5 | ) |
| 方程右边 = | 6 | − | 2 | × | 2 | x | + | 2 | × | 5 |
| = | 6 | − | 4 | x | + | 10 |
| = | 16 | − | 4 | x |
| - | 1 | x | − | 4 | = | 16 | − | 4 | x |
| - | 1 | x | + | 4 | x | = | 16 | + | 4 |
| 3 | x | = | 16 | + | 4 |
| 3 | x | = | 20 |
| x | = | 20 | ÷ | 3 |
| = | 20 | × | 1 3 |
| x | = | 20 3 |
| x | = | 6.666667 |