| ( | 3 | X | − | 15 100 | ) | ÷ | ( | 15 100 | − | X | ) | = | 3 | ÷ | 1 |
| 方程两边同时乘以: | ( | 15 100 | − | X | ) |
| ( | 3 | X | − | 15 100 | ) | = | 3 | ÷ | 1 | × | ( | 15 100 | − | X | ) |
| 3 | X | − | 15 100 | = | 3 | ÷ | 1 | × | ( | 15 100 | − | X | ) |
| 3 | X | − | 15 100 | = | 3 | ÷ | 1 | × | 15 100 | − | 3 | ÷ | 1 | × | X |
| 3 | X | − | 15 100 | = | 9 20 | − | 3 | X |
| 3 | X | + | 3 | X | = | 9 20 | + | 15 100 |
| 6 | X | = | 9 20 | + | 15 100 |
| 6 | X | = | 3 5 |
| X | = | 3 5 | ÷ | 6 |
| = | 3 5 | × | 1 6 |
| = | 1 5 | × | 1 2 |
| X | = | 1 10 |
| X | = | 0.1 |