| 1 | + | 2 | ( | 3 | x | × | 6 | ) | − | 1 | + | 2 | ( | 3 | x | × | 6 | ) | = | 0 |
| 方程左边 = | 0 | + | 2 | ( | 3 | x | × | 6 | ) | + | 2 | ( | 3 | x | × | 6 | ) |
| 0 | + | 2 | ( | 3 | x | × | 6 | ) | + | 2 | ( | 3 | x | × | 6 | ) | = | 0 |
| 方程左边 = | 0 | + | 2 | × | 3 | x | × | 6 | + | 2 | ( | 3 | x | × | 6 | ) |
| = | 0 | + | 36 | x | + | 2 | ( | 3 | x | × | 6 | ) |
| = | 0 | + | 36 | x | + | 2 | × | 3 | x | × | 6 |
| = | 0 | + | 36 | x | + | 36 | x |
| = | 0 | + | 72 | x |
| 72 | x | = | 0 |
| x | = | 0 | ÷ | 72 |
| = | 0 | × | 1 72 |
| x | = | 0 |