| ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | - | a | ) | + | ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | 6 | + | a | ) | = | 48 |
| - | 12 | ÷ | a | × | ( | - | a | ) | + | a | ( | - | a | ) | + | 4 | ( | - | a | ) | + | ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | 6 | + | a | ) | = | 48 |
| 12 | ÷ | 1 | × | 1 | + | a | ( | - | a | ) | + | 4 | ( | - | a | ) | + | ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | 6 | + | a | ) | = | 48 |
| 12 | + | a | ( | - | a | ) | + | 4 | ( | - | a | ) | + | ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | 6 | + | a | ) | = | 48 |
| 12 | − | a | a | + | 4 | ( | - | a | ) | + | ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | 6 | + | a | ) | = | 48 |
| 12 | − | a | a | − | 4 | a | + | ( | - | 12 | ÷ | a | + | a | + | 4 | ) | ( | 6 | + | a | ) | = | 48 |
| 12 | − | a | a | − | 4 | a | − | 12 | ÷ | a | × | ( | 6 | + | a | ) | + | a | ( | 6 | + | a | ) | + | 4 | ( | 6 | + | a | ) | = | 48 |
| 方程两边同时乘以: | a |
| 12 | a | − | a | a | a | − | 4 | a | a | − | 12 | ( | 6 | + | a | ) | + | a | ( | 6 | + | a | ) | = | 48 | a |
| 12 | a | − | a | a | a | − | 4 | a | a | − | 12 | × | 6 | − | 12 | a | = | 48 | a |
| 12 | a | − | a | a | a | − | 4 | a | a | − | 72 | − | 12 | a | + | a | = | 48 | a |
| 0 | a | − | a | a | a | − | 4 | a | a | − | 72 | + | a | ( | 6 | + | a | ) | a | = | 48 | a |
| - | a | a | a | − | 4 | a | a | − | 72 | + | a | × | 6 | a | + | a | a | = | 48 | a |
| - | a | a | a | − | 4 | a | a | − | 72 | + | a | × | 6 | a | + | a | a | = | 48 | a |
| - | a | a | a | − | 4 | a | a | − | 72 | + | a | × | 6 | a | + | a | a | = | 48 | a |