| 3 | ( | 20 | − | 2 | x | + | x | ) | ÷ | 6 | = | 7 |
| Left side of the equation = | 1 2 | ( | 20 | − | 2 | x | + | x | ) |
1 2 | ( | 20 | − | 2 | x | + | x | ) | = | 7 |
| Left side of the equation = | 1 2 | × | 20 | − | 1 2 | × | 2 | x | + | 1 2 | x |
| = | 10 | − | 1 | x | + | 1 2 | x |
| = | 10 | − | 1 2 | x |
| 10 | − | 1 2 | x | = | 7 |
| - | 1 2 | x | = | 7 | − | 10 |
| - | 1 2 | x | = | - | 3 |
| 3 | = | 1 2 | x |
1 2 | x | = | 3 |
| x | = | 3 | ÷ | 1 2 |
| = | 3 | × | 2 |
| x | = | 6 |