| ( | 100 | − | X | ) | × | 9 5 | + | 11 10 | X | = | 100 | ( | 1 | + | 2 5 | ) |
| 方程左边 = | 100 | × | 9 5 | − | X | × | 9 5 | + | 11 10 | X |
| = | 180 | − | X | × | 9 5 | + | 11 10 | X |
| = | 180 | − | 7 10 | X |
| 180 | − | 7 10 | X | = | 100 | ( | 1 | + | 2 5 | ) |
| 方程右边 = | 100 | × | 1 | + | 100 | × | 2 5 |
| = | 100 | + | 40 |
| = | 140 |
| 180 | − | 7 10 | X | = | 140 |
| - | 7 10 | X | = | 140 | − | 180 |
| - | 7 10 | X | = | - | 40 |
| 40 | = | 7 10 | X |
7 10 | X | = | 40 |
| X | = | 40 | ÷ | 7 10 |
| = | 40 | × | 10 7 |
| X | = | 400 7 |
| X | = | 57.142857 |