| 12 | ÷ | ( | 8 | + | 4 | ( | - | 2 | x | + | 1 | ) | ) | + | 13 | = | 12 |
| 方程两边同时乘以: | ( | 8 | + | 4 | ( | - | 2 | x | + | 1 | ) | ) |
| 12 | + | 13 | ( | 8 | + | 4 | ( | - | 2 | x | + | 1 | ) | ) | = | 12 | ( | 8 | + | 4 | ( | - | 2 | x | + | 1 | ) | ) |
| 12 | + | 13 | × | 8 | + | 13 | × | 4 | ( | - | 2 | x | + | 1 | ) | = | 12 | ( | 8 | + | 4 | ( | - | 2 | x | + | 1 | ) | ) |
| 12 | + | 13 | × | 8 | + | 13 | × | 4 | ( | - | 2 | x | + | 1 | ) | = | 12 | × | 8 | + | 12 | × | 4 | ( | - | 2 | x | + | 1 | ) |
| 12 | + | 104 | + | 52 | ( | - | 2 | x | + | 1 | ) | = | 96 | + | 48 | ( | - | 2 | x | + | 1 | ) |
| 116 | + | 52 | ( | - | 2 | x | + | 1 | ) | = | 96 | + | 48 | ( | - | 2 | x | + | 1 | ) |
| 116 | − | 52 | × | 2 | x | + | 52 | × | 1 | = | 96 | + | 48 | ( | - | 2 | x | + | 1 | ) |
| 116 | − | 52 | × | 2 | x | + | 52 | × | 1 | = | 96 | − | 48 | × | 2 | x | + | 48 | × | 1 |
| 116 | − | 104 | x | + | 52 | = | 96 | − | 96 | x | + | 48 |
| 168 | − | 104 | x | = | 144 | − | 96 | x |
| - | 104 | x | + | 96 | x | = | 144 | − | 168 |
| - | 8 | x | = | 144 | − | 168 |
| - | 8 | x | = | - | 24 |
| 24 | = | 8 | x |
| 8 | x | = | 24 |
| x | = | 24 | ÷ | 8 |
| = | 24 | × | 1 8 |
| = | 3 | × | 1 |
| x | = | 3 |