| 7 | x | + | 2 | ( | 3 | x | − | 3 | ) | = | 20 |
| Left side of the equation = | 7 | x | + | 2 | × | 3 | x | − | 2 | × | 3 |
| = | 7 | x | + | 6 | x | − | 6 |
| = | 13 | x | − | 6 |
| 13 | x | − | 6 | = | 20 |
| 13 | x | = | 20 | + | 6 |
| 13 | x | = | 26 |
| x | = | 26 | ÷ | 13 |
| = | 26 | × | 1 13 |
| = | 2 | × | 1 |
| x | = | 2 |
| 7 | x | + | 6 | x | = | 26 |
| Left side of the equation = | 13 | x |
| 13 | x | = | 26 |
| x | = | 26 | ÷ | 13 |
| = | 26 | × | 1 13 |
| = | 2 | × | 1 |
| x | = | 2 |