| ( | 100 | x | ) | ÷ | ( | 120 | ( | 14 | − | x | ) | ) | = | 1 | ÷ | 3 |
| 方程两边同时乘以: | ( | 120 | ( | 14 | − | x | ) | ) |
| ( | 100 | x | ) | = | 1 | ÷ | 3 | × | ( | 120 | ( | 14 | − | x | ) | ) |
| 100 | x | = | 1 | ÷ | 3 | × | ( | 120 | ( | 14 | − | x | ) | ) |
| 100 | x | = | 1 | ÷ | 3 | × | 120 | ( | 14 | − | x | ) |
| 100 | x | = | 40 | ( | 14 | − | x | ) |
| 100 | x | = | 40 | × | 14 | − | 40 | x |
| 100 | x | = | 560 | − | 40 | x |
| 100 | x | + | 40 | x | = | 560 |
| 140 | x | = | 560 |
| x | = | 560 | ÷ | 140 |
| = | 560 | × | 1 140 |
| = | 4 | × | 1 |
| x | = | 4 |