| 2 | ( | - | 15 | ÷ | ( | 2 | x | + | 9 | ) | + | 1 | ) | + | 18 | = | 10 |
| - | 2 | × | 15 | ÷ | ( | 2 | x | + | 9 | ) | + | 2 | × | 1 | + | 18 | = | 10 |
| - | 30 | ÷ | ( | 2 | x | + | 9 | ) | + | 2 | + | 18 | = | 10 |
| - | 30 | ÷ | ( | 2 | x | + | 9 | ) | + | 20 | = | 10 |
| 方程两边同时乘以: | ( | 2 | x | + | 9 | ) |
| - | 30 | + | 20 | ( | 2 | x | + | 9 | ) | = | 10 | ( | 2 | x | + | 9 | ) |
| - | 30 | + | 20 | × | 2 | x | + | 20 | × | 9 | = | 10 | ( | 2 | x | + | 9 | ) |
| - | 30 | + | 20 | × | 2 | x | + | 20 | × | 9 | = | 10 | × | 2 | x | + | 10 | × | 9 |
| - | 30 | + | 40 | x | + | 180 | = | 20 | x | + | 90 |
| 150 | + | 40 | x | = | 20 | x | + | 90 |
| 40 | x | − | 20 | x | = | 90 | − | 150 |
| 20 | x | = | 90 | − | 150 |
| 20 | x | = | - | 60 |
| x | = | - | 60 | ÷ | 20 |
| = | - | 60 | × | 1 20 |
| = | - | 3 | × | 1 |
| x | = | - | 3 |