| ( | 9 | ÷ | ( | x | − | 4 | ) | ) | + | 13 | = | 102 | ÷ | ( | x | + | 12 | ) |
| 方程两边同时乘以: | ( | x | + | 12 | ) |
| ( | 9 | ÷ | ( | x | − | 4 | ) | ) | ( | x | + | 12 | ) | + | 13 | ( | x | + | 12 | ) | = | 102 |
| 9 | ÷ | ( | x | − | 4 | ) | × | ( | x | + | 12 | ) | + | 13 | ( | x | + | 12 | ) | = | 102 |
| 方程两边同时乘以: | ( | x | − | 4 | ) |
| 9 | ( | x | + | 12 | ) | + | 13 | ( | x | + | 12 | ) | ( | x | − | 4 | ) | = | 102 | ( | x | − | 4 | ) |
| 9 | x | + | 9 | × | 12 | + | 13 | ( | x | + | 12 | ) | ( | x | − | 4 | ) | = | 102 | ( | x | − | 4 | ) |
| 9 | x | + | 9 | × | 12 | + | 13 | ( | x | + | 12 | ) | ( | x | − | 4 | ) | = | 102 | x | − | 102 | × | 4 |
| 9 | x | + | 108 | + | 13 | ( | x | + | 12 | ) | ( | x | − | 4 | ) | = | 102 | x | − | 408 |
| 9 | x | + | 108 | + | 13 | x | ( | x | − | 4 | ) | + | 13 | × | 12 | ( | x | − | 4 | ) | = | 102 | x | − | 408 |
| 9 | x | + | 108 | + | 13 | x | ( | x | − | 4 | ) | + | 156 | ( | x | − | 4 | ) | = | 102 | x | − | 408 |
| 9 | x | + | 108 | + | 13 | x | x | − | 13 | x | × | 4 | + | 156 | ( | x | − | 4 | ) | = | 102 | x | − | 408 |
| 9 | x | + | 108 | + | 13 | x | x | − | 52 | x | + | 156 | ( | x | − | 4 | ) | = | 102 | x | − | 408 |
| - | 43 | x | + | 108 | + | 13 | x | x | + | 156 | ( | x | − | 4 | ) | = | 102 | x | − | 408 |
| - | 43 | x | + | 108 | + | 13 | x | x | + | 156 | x | − | 156 | × | 4 | = | 102 | x | − | 408 |
| - | 43 | x | + | 108 | + | 13 | x | x | + | 156 | x | − | 624 | = | 102 | x | − | 408 |
| 113 | x | − | 516 | + | 13 | x | x | = | 102 | x | − | 408 |