| 2 | × | 10 | ( | 20 | − | x | ) | = | 5 | × | 12 | x |
| Left side of the equation = | 20 | ( | 20 | − | x | ) |
| 20 | ( | 20 | − | x | ) | = | 5 | × | 12 | x |
| Left side of the equation = | 20 | × | 20 | − | 20 | x |
| = | 400 | − | 20 | x |
| 400 | − | 20 | x | = | 5 | × | 12 | x |
| Right side of the equation = | 60 | x |
| 400 | − | 20 | x | = | 60 | x |
| - | 20 | x | − | 60 | x | = | - | 400 |
| - | 80 | x | = | - | 400 |
| 400 | = | 80 | x |
| 80 | x | = | 400 |
| x | = | 400 | ÷ | 80 |
| = | 400 | × | 1 80 |
| = | 5 | × | 1 |
| x | = | 5 |