| 6 | ( | 12 | + | 3 | ( | 19 | + | 2 | x | ) | ) | + | 9 | = | - | 9 |
| 方程左边 = | 6 | × | 12 | + | 6 | × | 3 | ( | 19 | + | 2 | x | ) | + | 9 |
| = | 72 | + | 18 | ( | 19 | + | 2 | x | ) | + | 9 |
| = | 81 | + | 18 | ( | 19 | + | 2 | x | ) |
| = | 81 | + | 18 | × | 19 | + | 18 | × | 2 | x |
| = | 81 | + | 342 | + | 36 | x |
| = | 423 | + | 36 | x |
| 423 | + | 36 | x | = | - | 9 |
| 36 | x | = | - | 9 | − | 423 |
| 36 | x | = | - | 432 |
| x | = | - | 432 | ÷ | 36 |
| = | - | 432 | × | 1 36 |
| = | - | 12 | × | 1 |
| x | = | - | 12 |