| 28 | x | − | ( | 27 | − | 1 10 | ( | x | − | 1 | ) | ) | x | + | 1 2 | x | = | 12 |
| 方程左边 = | 57 2 | x | − | ( | 27 | − | 1 10 | ( | x | − | 1 | ) | ) | x |
57 2 | x | − | ( | 27 | − | 1 10 | ( | x | − | 1 | ) | ) | x | = | 12 |
| 方程左边 = | 57 2 | x | − | 27 | x | + | 1 10 | ( | x | − | 1 | ) | x |
| = | 3 2 | x | + | 1 10 | ( | x | − | 1 | ) | x |
| = | 3 2 | x | + | 1 10 | x | x | − | 1 10 | × | 1 | x |
| = | 3 2 | x | + | 1 10 | x | x | − | 1 10 | x |
| = | 7 5 | x | + | 1 10 | x | x |
7 5 | x | + | 1 10 | x | x | = | 12 |