| ( | 343 | + | X | ) | ÷ | ( | 266 | + | X | ) | = | 19 20 |
| 方程两边同时乘以: | ( | 266 | + | X | ) |
| ( | 343 | + | X | ) | = | 19 20 | ( | 266 | + | X | ) |
| 343 | + | X | = | 19 20 | ( | 266 | + | X | ) |
| 343 | + | X | = | 19 20 | × | 266 | + | 19 20 | X |
| 343 | + | X | = | 2527 10 | + | 19 20 | X |
| X | − | 19 20 | X | = | 2527 10 | − | 343 |
1 20 | X | = | 2527 10 | − | 343 |
1 20 | X | = | - | 903 10 |
| X | = | - | 903 10 | ÷ | 1 20 |
| = | - | 903 10 | × | 20 |
| = | - | 903 | × | 2 |
| X | = | - | 1806 |