| ( | 4 | ÷ | 15 | ) | ÷ | ( | 4 | ÷ | 25 | ) | = | ( | 4 | ÷ | 15 | ) | ÷ | ( | 4 | ÷ | x | ) |
| 方程两边同时乘以: | ( | 4 | ÷ | 25 | ) | , | ( | 4 | ÷ | x | ) |
| ( | 4 | ÷ | 15 | ) | ( | 4 | ÷ | x | ) | = | ( | 4 | ÷ | 15 | ) | ( | 4 | ÷ | 25 | ) |
| 4 | ÷ | 15 | × | ( | 4 | ÷ | x | ) | = | ( | 4 | ÷ | 15 | ) | ( | 4 | ÷ | 25 | ) |
| 4 | ÷ | 15 | × | ( | 4 | ÷ | x | ) | = | 4 | ÷ | 15 | × | ( | 4 | ÷ | 25 | ) |
4 15 | ( | 4 | ÷ | x | ) | = | 4 15 | ( | 4 | ÷ | 25 | ) |
4 15 | × | 4 | ÷ | x | = | 4 15 | ( | 4 | ÷ | 25 | ) |
4 15 | × | 4 | ÷ | x | = | 4 15 | × | 4 | ÷ | 25 |
16 15 | ÷ | x | = | 16 375 |
| 方程两边同时乘以: | x |
16 15 | = | 16 375 | x |
| - | 16 375 | x | = | - | 16 15 |
16 15 | = | 16 375 | x |
16 375 | x | = | 16 15 |
| x | = | 16 15 | ÷ | 16 375 |
| = | 16 15 | × | 375 16 |
| = | 1 | × | 25 |
| x | = | 25 |