128 5 | − | ( | 25 | − | 1 5 | ( | x | − | 1 | ) | ) | x | + | 3 5 | x | = | 84 5 |
| 方程左边 = | 128 5 | − | 25 | x | + | 1 5 | ( | x | − | 1 | ) | x | + | 3 5 | x |
| = | 128 5 | − | 122 5 | x | + | 1 5 | ( | x | − | 1 | ) | x |
| = | 128 5 | − | 122 5 | x | + | 1 5 | x | x | − | 1 5 | × | 1 | x |
| = | 128 5 | − | 122 5 | x | + | 1 5 | x | x | − | 1 5 | x |
| = | 128 5 | − | 123 5 | x | + | 1 5 | x | x |
128 5 | − | 123 5 | x | + | 1 5 | x | x | = | 84 5 |