| 14 | + | 12 5 | ( | x | − | 3 | ) | + | 89 5 | = | 12 |
| 方程左边 = | 159 5 | + | 12 5 | ( | x | − | 3 | ) |
159 5 | + | 12 5 | ( | x | − | 3 | ) | = | 12 |
| 方程左边 = | 159 5 | + | 12 5 | x | − | 12 5 | × | 3 |
| = | 159 5 | + | 12 5 | x | − | 36 5 |
| = | 123 5 | + | 12 5 | x |
123 5 | + | 12 5 | x | = | 12 |
12 5 | x | = | 12 | − | 123 5 |
12 5 | x | = | - | 63 5 |
| x | = | - | 63 5 | ÷ | 12 5 |
| = | - | 63 5 | × | 5 12 |
| = | - | 21 | × | 1 4 |
| x | = | - | 21 4 |
| x | = | - 5.25 |