| 12 | ÷ | X | − | 12 | ÷ | ( | X | + | 4 | ) | = | 4 |
| 方程两边同时乘以: | X |
| 12 | − | 12 | ÷ | ( | X | + | 4 | ) | × | X | = | 4 | X |
| 方程两边同时乘以: | ( | X | + | 4 | ) |
| 12 | ( | X | + | 4 | ) | − | 12 | X | = | 4 | X | ( | X | + | 4 | ) |
| 12 | X | + | 12 | × | 4 | − | 12 | X | = | 4 | X | ( | X | + | 4 | ) |
| 12 | X | + | 12 | × | 4 | − | 12 | X | = | 4 | X | X | + | 4 | X | × | 4 |
| 12 | X | + | 48 | − | 12 | X | = | 4 | X | X | + | 16 | X |
| 0 | X | + | 48 | = | 4 | X | X | + | 16 | X |