| 20 | + | x | = | 1 | ÷ | 3 | × | ( | 5 | x | + | 20 | ) |
| 方程右边 = | 1 3 | ( | 5 | x | + | 20 | ) |
| 20 | + | x | = | 1 3 | ( | 5 | x | + | 20 | ) |
| 方程右边 = | 1 3 | × | 5 | x | + | 1 3 | × | 20 |
| = | 5 3 | x | + | 20 3 |
| 20 | + | x | = | 5 3 | x | + | 20 3 |
| x | − | 5 3 | x | = | 20 3 | − | 20 |
| - | 2 3 | x | = | 20 3 | − | 20 |
| - | 2 3 | x | = | - | 40 3 |
40 3 | = | 2 3 | x |
2 3 | x | = | 40 3 |
| x | = | 40 3 | ÷ | 2 3 |
| = | 40 3 | × | 3 2 |
| = | 20 | × | 1 |
| x | = | 20 |