| X | × | 1 4 | + | ( | 1 | − | X | ) | ( | - | 1 5 | ) | = | 1 50 |
| 方程左边 = | 1 4 | X | + | 1 | ( | - | 1 5 | ) | − | X | ( | - | 1 5 | ) |
| = | 1 4 | X | − | 1 | × | 1 5 | − | X | ( | - | 1 5 | ) |
| = | 1 4 | X | − | 1 5 | − | X | ( | - | 1 5 | ) |
| = | 1 4 | X | − | 1 5 | + | X | × | 1 5 |
| = | 9 20 | X | − | 1 5 |
9 20 | X | − | 1 5 | = | 1 50 |
9 20 | X | = | 1 50 | + | 1 5 |
9 20 | X | = | 11 50 |
| X | = | 11 50 | ÷ | 9 20 |
| = | 11 50 | × | 20 9 |
| = | 11 5 | × | 2 9 |
| X | = | 22 45 |
| X | = | 0.488889 |