| ( | 3 | + | 9 | ÷ | ( | x | − | 3 | ) | ) | x | = | - | 200 | ÷ | 7 |
| 3 | x | + | 9 | ÷ | ( | x | − | 3 | ) | × | x | = | - | 200 | ÷ | 7 |
| 3 | x | + | 9 | ÷ | ( | x | − | 3 | ) | × | x | = | - | 200 7 |
| 方程两边同时乘以: | ( | x | − | 3 | ) |
| 3 | x | ( | x | − | 3 | ) | + | 9 | x | = | - | 200 7 | ( | x | − | 3 | ) |
| 3 | x | x | − | 3 | x | × | 3 | + | 9 | x | = | - | 200 7 | ( | x | − | 3 | ) |
| 3 | x | x | − | 3 | x | × | 3 | + | 9 | x | = | - | 200 7 | x | + | 200 7 | × | 3 |
| 3 | x | x | − | 9 | x | + | 9 | x | = | - | 200 7 | x | + | 600 7 |
| 3 | x | x | − | 0 | x | = | - | 200 7 | x | + | 600 7 |