| - | 99 | ÷ | ( | 15 | + | 8 | ( | 2 | x | + | 4 | ) | ) | + | 6 | = | 9 |
| Multiply both sides of the equation by: | ( | 15 | + | 8 | ( | 2 | x | + | 4 | ) | ) |
| - | 99 | + | 6 | ( | 15 | + | 8 | ( | 2 | x | + | 4 | ) | ) | = | 9 | ( | 15 | + | 8 | ( | 2 | x | + | 4 | ) | ) |
| - | 99 | + | 6 | × | 15 | + | 6 | × | 8 | ( | 2 | x | + | 4 | ) | = | 9 | ( | 15 | + | 8 | ( | 2 | x | + | 4 | ) | ) |
| - | 99 | + | 6 | × | 15 | + | 6 | × | 8 | ( | 2 | x | + | 4 | ) | = | 9 | × | 15 | + | 9 | × | 8 | ( | 2 | x | + | 4 | ) |
| - | 99 | + | 90 | + | 48 | ( | 2 | x | + | 4 | ) | = | 135 | + | 72 | ( | 2 | x | + | 4 | ) |
| - | 9 | + | 48 | ( | 2 | x | + | 4 | ) | = | 135 | + | 72 | ( | 2 | x | + | 4 | ) |
| - | 9 | + | 48 | × | 2 | x | + | 48 | × | 4 | = | 135 | + | 72 | ( | 2 | x | + | 4 | ) |
| - | 9 | + | 48 | × | 2 | x | + | 48 | × | 4 | = | 135 | + | 72 | × | 2 | x | + | 72 | × | 4 |
| - | 9 | + | 96 | x | + | 192 | = | 135 | + | 144 | x | + | 288 |
| 183 | + | 96 | x | = | 423 | + | 144 | x |
| 96 | x | − | 144 | x | = | 423 | − | 183 |
| - | 48 | x | = | 423 | − | 183 |
| - | 48 | x | = | 240 |
| - | 240 | = | 48 | x |
| 48 | x | = | - | 240 |
| x | = | - | 240 | ÷ | 48 |
| = | - | 240 | × | 1 48 |
| = | - | 5 | × | 1 |
| x | = | - | 5 |