| x | ( | ( | x | + | 1 | ) | ( | x | + | 1 2 | ) | + | 7 | ÷ | 20 | ) | − | ( | - | 7 | ÷ | 40 | + | ( | x | − | 1 | ) | ÷ | 20 | ) | = | 0 |
| 方程左边 = | x | ( | x | + | 1 | ) | ( | x | + | 1 2 | ) | + | x | × | 7 | ÷ | 20 | − | ( | - | 7 | ÷ | 40 | + | ( | x | − | 1 | ) | ÷ | 20 | ) |
| = | x | ( | x | + | 1 | ) | ( | x | + | 1 2 | ) | + | x | × | 7 20 | − | ( | - | 7 | ÷ | 40 | + | ( | x | − | 1 | ) | ÷ | 20 | ) |
| = | x | x | ( | x | + | 1 2 | ) | + | x | × | 1 | ( | x | + | 1 2 | ) | + | 7 20 | x | − | ( | - | 7 | ÷ | 40 | + | ( | x | − | 1 | ) | ÷ | 20 | ) |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | ( | x | + | 1 2 | ) | + | 7 20 | x | − | ( | - | 7 | ÷ | 40 | + | ( | x | − | 1 | ) | ÷ | 20 | ) |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | x | × | 1 | × | 1 2 |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | x | × | 1 2 | + | 7 20 |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 17 20 | x | − | ( | - | 7 | ÷ | 40 | + | ( | x | − | 1 | ) | ÷ | 20 | ) |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 17 20 | x | + | 7 |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 17 20 | x | + | 7 40 |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 17 20 | x | + | 7 40 |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 17 20 | x | + | 7 40 |
| = | x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 4 5 | x | + | 9 40 |
| x | x | x | + | x | x | × | 1 2 | + | x | × | 1 | x | + | 4 5 | x | + | 9 40 | = | 0 |