| x | ÷ | 12 | = | x | ÷ | 15 | + | ( | 20 | + | 4 | ) | x | ÷ | 12 | × | 60 |
| 方程右边 = | x | × | 1 15 | + | ( | 20 | + | 4 | ) | x | × | 5 |
1 12 | x | = | 1 15 | x | + | ( | 20 | + | 4 | ) | x | × | 5 |
| 方程右边 = | 1 15 | x | + | 20 | x | × | 5 | + | 4 | x | × | 5 |
| = | 1 15 | x | + | 100 | x | + | 20 | x |
| = | 1801 15 | x |
1 12 | x | = | 1801 15 | x |
1 12 | x | − | 1801 15 | x | = | 0 |
| - | 7199 60 | x | = | 0 |
| - | 0 | = | 7199 60 | x |
7199 60 | x | = | - | 0 |
| x | = | - | 0 | ÷ | 7199 60 |
| = | - | 0 | × | 60 7199 |
| x | = | 0 |