| ( | X | + | 10 | ) | ÷ | 7200 | = | ( | 3 2 | X | ) | ÷ | 5400 |
| 方程左边 = | X | × | 1 7200 | + | 10 | × | 1 7200 |
| = | X | × | 1 7200 | + | 1 720 |
1 7200 | X | + | 1 720 | = | ( | 3 2 | X | ) | ÷ | 5400 |
| 方程右边 = | 3 2 | X | × | 1 5400 |
| = | 1 3600 | X |
1 7200 | X | + | 1 720 | = | 1 3600 | X |
1 7200 | X | − | 1 3600 | X | = | - | 1 720 |
| - | 1 7200 | X | = | - | 1 720 |
1 720 | = | 1 7200 | X |
1 7200 | X | = | 1 720 |
| X | = | 1 720 | ÷ | 1 7200 |
| = | 1 720 | × | 7200 |
| = | 1 | × | 10 |
| X | = | 10 |