| ( | X | − | 200 | ) | ÷ | 3300 | = | ( | X | − | 350 | ) | ÷ | 3000 |
| 方程左边 = | X | × | 1 3300 | − | 200 | × | 1 3300 |
| = | X | × | 1 3300 | − | 2 33 |
1 3300 | X | − | 2 33 | = | ( | X | − | 350 | ) | ÷ | 3000 |
| 方程右边 = | X | × | 1 3000 | − | 350 | × | 1 3000 |
| = | X | × | 1 3000 | − | 7 60 |
1 3300 | X | − | 2 33 | = | 1 3000 | X | − | 7 60 |
1 3300 | X | − | 1 3000 | X | = | - | 7 60 | + | 2 33 |
| - | 1 33000 | X | = | - | 7 60 | + | 2 33 |
| - | 1 33000 | X | = | - | 37 660 |
37 660 | = | 1 33000 | X |
1 33000 | X | = | 37 660 |
| X | = | 37 660 | ÷ | 1 33000 |
| = | 37 660 | × | 33000 |
| = | 37 | × | 50 |
| X | = | 1850 |