| 240 | ( | 6 | − | x | ) | = | 3 | × | 40 | x |
| Left side of the equation = | 240 | × | 6 | − | 240 | x |
| = | 1440 | − | 240 | x |
| 1440 | − | 240 | x | = | 3 | × | 40 | x |
| Right side of the equation = | 120 | x |
| 1440 | − | 240 | x | = | 120 | x |
| - | 240 | x | − | 120 | x | = | - | 1440 |
| - | 360 | x | = | - | 1440 |
| 1440 | = | 360 | x |
| 360 | x | = | 1440 |
| x | = | 1440 | ÷ | 360 |
| = | 1440 | × | 1 360 |
| = | 4 | × | 1 |
| x | = | 4 |