| x | + | 2 | x | + | ( | x | + | 2 | x | − | 15 | ) | = | 65 |
| Left side of the equation = | 3 | x | + | ( | x | + | 2 | x | − | 15 | ) |
| 3 | x | + | ( | x | + | 2 | x | − | 15 | ) | = | 65 |
| Left side of the equation = | 3 | x | + | x | + | 2 | x | − | 15 |
| = | 6 | x | − | 15 |
| 6 | x | − | 15 | = | 65 |
| 6 | x | = | 65 | + | 15 |
| 6 | x | = | 80 |
| x | = | 80 | ÷ | 6 |
| = | 80 | × | 1 6 |
| = | 40 | × | 1 3 |
| x | = | 40 3 |
| x | = | 13.333333 |