| 3 | x | + | 4 | + | 5 | = | 6 | ( | x | − | 5 | ) |
| Left side of the equation = | 3 | x | + | 9 |
| 3 | x | + | 9 | = | 6 | ( | x | − | 5 | ) |
| Right side of the equation = | 6 | x | − | 6 | × | 5 |
| = | 6 | x | − | 30 |
| 3 | x | + | 9 | = | 6 | x | − | 30 |
| 3 | x | − | 6 | x | = | - | 30 | − | 9 |
| - | 3 | x | = | - | 30 | − | 9 |
| - | 3 | x | = | - | 39 |
| 39 | = | 3 | x |
| 3 | x | = | 39 |
| x | = | 39 | ÷ | 3 |
| = | 39 | × | 1 3 |
| = | 13 | × | 1 |
| x | = | 13 |