12 5 | × | 670 | ÷ | ( | X | + | 670 | ) | = | 27 20 |
| 方程两边同时乘以: | ( | X | + | 670 | ) |
12 5 | × | 670 | = | 27 20 | ( | X | + | 670 | ) |
12 5 | × | 670 | = | 27 20 | X | + | 27 20 | × | 670 |
| 1608 | = | 27 20 | X | + | 1809 2 |
| - | 27 20 | X | = | 1809 2 | − | 1608 |
| - | 27 20 | X | = | - | 1407 2 |
1407 2 | = | 27 20 | X |
27 20 | X | = | 1407 2 |
| X | = | 1407 2 | ÷ | 27 20 |
| = | 1407 2 | × | 20 27 |
| = | 469 | × | 10 9 |
| X | = | 4690 9 |
| X | = | 521.111111 |