| 4 | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) | = | x |
| 方程左边 = | 4 | × | 1 | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) | − | 4 | ( | 1 10 | x | ) | ÷ | 12 5 | × | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) | − | 5 3 | ( | 1 10 | x | ) | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | × | 1 | − | 4 | ( | 1 10 | x | ) | ÷ | 12 5 | − | 5 3 | ( | 1 10 | x | ) | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | − | 5 3 | ( | 1 10 | x | ) | − | 5 3 | ( | 1 10 | x | ) | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | − | 5 3 | × | 1 10 | x | − | 5 3 | ( | 1 10 | x | ) | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | − | 1 6 | x | − | 5 3 | ( | 1 10 | x | ) | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | − | 1 6 | x | − | 5 3 | × | 1 10 | x | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | − | 1 6 | x | − | 1 6 | x | ( | 1 | − | ( | 1 10 | x | ) | ÷ | 12 5 | ) |
| = | 4 | − | 1 6 | x | − | 1 6 | x | × | 1 | + | 1 6 | x | ( | 1 10 | x | ) | ÷ | 12 5 |
| = | 4 | − | 1 6 | x | − | 1 6 | x | + | 5 72 | x | ( | 1 10 | x | ) |
| = | 4 | − | 1 3 | x | + | 5 72 | x | ( | 1 10 | x | ) |
| = | 4 | − | 1 3 | x | + | 5 72 | x | × | 1 10 | x |
| = | 4 | − | 1 3 | x | + | 1 144 | x | x |
| 4 | − | 1 3 | x | + | 1 144 | x | x | = | x |