| ( | 600 | x | ) | ÷ | 2 | = | ( | 400 | ( | 1300 | − | x | ) | ) | ÷ | 3 |
| Left side of the equation = | 600 | x | × | 1 2 |
| = | 300 | x |
| 300 | x | = | ( | 400 | ( | 1300 | − | x | ) | ) | ÷ | 3 |
| Right side of the equation = | 400 | ( | 1300 | − | x | ) | × | 1 3 |
| = | 400 3 | ( | 1300 | − | x | ) |
| = | 400 3 | × | 1300 | − | 400 3 | x |
| = | 520000 3 | − | 400 3 | x |
| 300 | x | = | 520000 3 | − | 400 3 | x |
| 300 | x | + | 400 3 | x | = | 520000 3 |
1300 3 | x | = | 520000 3 |
| x | = | 520000 3 | ÷ | 1300 3 |
| = | 520000 3 | × | 3 1300 |
| = | 400 | × | 1 |
| x | = | 400 |