| ( | 1 2 | − | 1 20 | ) | x | + | ( | - | 1 2 | − | 1 20 | ) | ( | 1 | − | x | ) | = | 0 |
| 方程左边 = | 1 2 | x | − | 1 20 | x | + | ( | - | 1 2 | − | 1 20 | ) | ( | 1 | − | x | ) |
| = | 9 20 | x | + | ( | - | 1 2 | − | 1 20 | ) | ( | 1 | − | x | ) |
| = | 9 20 | x | − | 1 2 | ( | 1 | − | x | ) | − | 1 20 | ( | 1 | − | x | ) |
| = | 9 20 | x | − | 1 2 | × | 1 | + | 1 2 | x | − | 1 20 | ( | 1 | − | x | ) |
| = | 9 20 | x | − | 1 2 | + | 1 2 | x | − | 1 20 | ( | 1 | − | x | ) |
| = | 19 20 | x | − | 1 2 | − | 1 20 | ( | 1 | − | x | ) |
| = | 19 20 | x | − | 1 2 | − | 1 20 | × | 1 | + | 1 20 | x |
| = | 19 20 | x | − | 1 2 | − | 1 20 | + | 1 20 | x |
| = | 1 | x | − | 11 20 |
| 1 | x | − | 11 20 | = | 0 |
| 1 | x | = | 0 | + | 11 20 |
| x | = | 0 | + | 11 20 |
| x | = | 11 20 |