| 8 | ( | 42 | ÷ | ( | x | + | 9 | ) | + | 8 | ) | + | 8 | = | 16 |
| 8 | × | 42 | ÷ | ( | x | + | 9 | ) | + | 8 | × | 8 | + | 8 | = | 16 |
| 336 | ÷ | ( | x | + | 9 | ) | + | 64 | + | 8 | = | 16 |
| 336 | ÷ | ( | x | + | 9 | ) | + | 72 | = | 16 |
| 方程两边同时乘以: | ( | x | + | 9 | ) |
| 336 | + | 72 | ( | x | + | 9 | ) | = | 16 | ( | x | + | 9 | ) |
| 336 | + | 72 | x | + | 72 | × | 9 | = | 16 | ( | x | + | 9 | ) |
| 336 | + | 72 | x | + | 72 | × | 9 | = | 16 | x | + | 16 | × | 9 |
| 336 | + | 72 | x | + | 648 | = | 16 | x | + | 144 |
| 984 | + | 72 | x | = | 16 | x | + | 144 |
| 72 | x | − | 16 | x | = | 144 | − | 984 |
| 56 | x | = | 144 | − | 984 |
| 56 | x | = | - | 840 |
| x | = | - | 840 | ÷ | 56 |
| = | - | 840 | × | 1 56 |
| = | - | 15 | × | 1 |
| x | = | - | 15 |