| 300 | x | + | 400 | ( | 50 | − | x | ) | = | 16000 |
| Left side of the equation = | 300 | x | + | 400 | × | 50 | − | 400 | x |
| = | 300 | x | + | 20000 | − | 400 | x |
| = | - | 100 | x | + | 20000 |
| - | 100 | x | + | 20000 | = | 16000 |
| - | 100 | x | = | 16000 | − | 20000 |
| - | 100 | x | = | - | 4000 |
| 4000 | = | 100 | x |
| 100 | x | = | 4000 |
| x | = | 4000 | ÷ | 100 |
| = | 4000 | × | 1 100 |
| = | 40 | × | 1 |
| x | = | 40 |