| ( | x | − | 5 | ) | ÷ | ( | ( | 50 | − | x | ) | − | 5 | ) | = | 2 | ÷ | 3 |
| 方程两边同时乘以: | ( | ( | 50 | − | x | ) | − | 5 | ) |
| ( | x | − | 5 | ) | = | 2 | ÷ | 3 | × | ( | ( | 50 | − | x | ) | − | 5 | ) |
| x | − | 5 | = | 2 | ÷ | 3 | × | ( | ( | 50 | − | x | ) | − | 5 | ) |
| x | − | 5 | = | 2 | ÷ | 3 | × | ( | 50 | − | x | ) | − | 2 | ÷ | 3 | × | 5 |
| x | − | 5 | = | 2 3 | ( | 50 | − | x | ) | − | 10 3 |
| x | − | 5 | = | 2 3 | × | 50 | − | 2 3 | x | − | 10 3 |
| x | − | 5 | = | 100 3 | − | 2 3 | x | − | 10 3 |
| x | − | 5 | = | 30 | − | 2 3 | x |
| x | + | 2 3 | x | = | 30 | + | 5 |
5 3 | x | = | 30 | + | 5 |
5 3 | x | = | 35 |
| x | = | 35 | ÷ | 5 3 |
| = | 35 | × | 3 5 |
| = | 7 | × | 3 |
| x | = | 21 |