| x | ( | 1 | − | 2 | ÷ | 3 | ) | + | ( | 60 | − | x | ) | ( | 1 | − | 3 | ÷ | 4 | ) | = | 20 |
| 方程左边 = | x | × | 1 | − | x | × | 2 | ÷ | 3 | + | ( | 60 | − | x | ) | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | x | × | 1 | − | x | × | 2 3 | + | ( | 60 | − | x | ) | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | 1 3 | x | + | ( | 60 | − | x | ) | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | 1 3 | x | + | 60 | ( | 1 | − | 3 | ÷ | 4 | ) | − | x | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | 1 3 | x | + | 60 | × | 1 | − | 60 | × | 3 | ÷ | 4 | − | x | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | 1 3 | x | + | 60 | − | 45 | − | x | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | 1 3 | x | + | 15 | − | x | ( | 1 | − | 3 | ÷ | 4 | ) |
| = | 1 3 | x | + | 15 | − | x | × | 1 | + | x | × | 3 | ÷ | 4 |
| = | 1 3 | x | + | 15 | − | x | × | 1 | + | x | × | 3 4 |
| = | 1 12 | x | + | 15 |
1 12 | x | + | 15 | = | 20 |
1 12 | x | = | 20 | − | 15 |
1 12 | x | = | 5 |
| x | = | 5 | ÷ | 1 12 |
| = | 5 | × | 12 |
| x | = | 60 |