| - | 9 | ( | 43 | + | 9 | x | ) | ÷ | 21 | + | 11 | x | = | - | 22 |
| 方程左边 = | - | 3 7 | ( | 43 | + | 9 | x | ) | + | 11 | x |
| - | 3 7 | ( | 43 | + | 9 | x | ) | + | 11 | x | = | - | 22 |
| 方程左边 = | - | 3 7 | × | 43 | − | 3 7 | × | 9 | x | + | 11 | x |
| = | - | 129 7 | − | 27 7 | x | + | 11 | x |
| = | - | 129 7 | + | 50 7 | x |
| - | 129 7 | + | 50 7 | x | = | - | 22 |
50 7 | x | = | - | 22 | + | 129 7 |
50 7 | x | = | - | 25 7 |
| x | = | - | 25 7 | ÷ | 50 7 |
| = | - | 25 7 | × | 7 50 |
| = | - | 1 | × | 1 2 |
| x | = | - | 1 2 |
| x | = | - 0.5 |