| - | 6 | ( | - | 45 | ÷ | ( | x | + | 7 | ) | + | 2 | ) | + | 6 | = | 12 |
| 6 | × | 45 | ÷ | ( | x | + | 7 | ) | − | 6 | × | 2 | + | 6 | = | 12 |
| 270 | ÷ | ( | x | + | 7 | ) | − | 12 | + | 6 | = | 12 |
| 270 | ÷ | ( | x | + | 7 | ) | − | 6 | = | 12 |
| 方程两边同时乘以: | ( | x | + | 7 | ) |
| 270 | − | 6 | ( | x | + | 7 | ) | = | 12 | ( | x | + | 7 | ) |
| 270 | − | 6 | x | − | 6 | × | 7 | = | 12 | ( | x | + | 7 | ) |
| 270 | − | 6 | x | − | 6 | × | 7 | = | 12 | x | + | 12 | × | 7 |
| 270 | − | 6 | x | − | 42 | = | 12 | x | + | 84 |
| 228 | − | 6 | x | = | 12 | x | + | 84 |
| - | 6 | x | − | 12 | x | = | 84 | − | 228 |
| - | 18 | x | = | 84 | − | 228 |
| - | 18 | x | = | - | 144 |
| 144 | = | 18 | x |
| 18 | x | = | 144 |
| x | = | 144 | ÷ | 18 |
| = | 144 | × | 1 18 |
| = | 8 | × | 1 |
| x | = | 8 |