| ( | ( | 1 | + | X | + | 3 20 | ) | ÷ | ( | 1 | + | X | ) | − | 1 | ) | = | 1 20 | ÷ | 3 5 |
| ( | 1 | + | X | + | 3 20 | ) | ÷ | ( | 1 | + | X | ) | − | 1 | = | 1 20 | ÷ | 3 5 |
| ( | 1 | + | X | + | 3 20 | ) | ÷ | ( | 1 | + | X | ) | − | 1 | = | 1 12 |
| 方程两边同时乘以: | ( | 1 | + | X | ) |
| ( | 1 | + | X | + | 3 20 | ) | − | 1 | ( | 1 | + | X | ) | = | 1 12 | ( | 1 | + | X | ) |
| 1 | + | X | + | 3 20 | − | 1 | ( | 1 | + | X | ) | = | 1 12 | ( | 1 | + | X | ) |
| 1 | + | X | + | 3 20 | − | 1 | ( | 1 | + | X | ) | = | 1 12 | × | 1 | + | 1 12 | X |
| 1 | + | X | + | 3 20 | − | 1 | ( | 1 | + | X | ) | = | 1 12 | + | 1 12 | X |
23 20 | + | X | − | 1 | ( | 1 | + | X | ) | = | 1 12 | + | 1 12 | X |
23 20 | + | X | − | 1 | × | 1 | − | 1 | X | = | 1 12 | + | 1 12 | X |
23 20 | + | X | − | 1 | − | 1 | X | = | 1 12 | + | 1 12 | X |
3 20 | + | 0 | X | = | 1 12 | + | 1 12 | X |
| - | 1 12 | X | = | 1 12 | − | 3 20 |
| - | 1 12 | X | = | - | 1 15 |
1 15 | = | 1 12 | X |
1 12 | X | = | 1 15 |
| X | = | 1 15 | ÷ | 1 12 |
| = | 1 15 | × | 12 |
| = | 1 5 | × | 4 |
| X | = | 4 5 |
| X | = | 0.8 |