| ( | 1 | − | 1 | ÷ | 5 | ) | x | − | ( | 1 | ÷ | 5 | × | x | + | 30 | ) | = | 3 |
| 方程左边 = | 1 | x | − | 1 | ÷ | 5 | × | x | − | ( | 1 | ÷ | 5 | × | x | + | 30 | ) |
| = | 1 | x | − | 1 5 | x | − | ( | 1 | ÷ | 5 | × | x | + | 30 | ) |
| = | 4 5 | x | − | ( | 1 | ÷ | 5 | × | x | + | 30 | ) |
| = | 4 5 | x | − | 1 | ÷ | 5 | × | x | − | 30 |
| = | 4 5 | x | − | 1 5 | x | − | 30 |
| = | 3 5 | x | − | 30 |
3 5 | x | − | 30 | = | 3 |
3 5 | x | = | 3 | + | 30 |
3 5 | x | = | 33 |
| x | = | 33 | ÷ | 3 5 |
| = | 33 | × | 5 3 |
| = | 11 | × | 5 |
| x | = | 55 |