| 3 | ÷ | 10 | × | ( | 200 | + | x | ) | − | 2 | ÷ | 10 | × | ( | 300 | − | x | ) | = | 300 | × | 9 | ÷ | 25 |
| Left side of the equation = | 3 10 | ( | 200 | + | x | ) | − | 1 5 | ( | 300 | − | x | ) |
3 10 | ( | 200 | + | x | ) | − | 1 5 | ( | 300 | − | x | ) | = | 300 | × | 9 | ÷ | 25 |
| Left side of the equation = | 3 10 | × | 200 | + | 3 10 | x | − | 1 5 | ( | 300 | − | x | ) |
| = | 60 | + | 3 10 | x | − | 1 5 | ( | 300 | − | x | ) |
| = | 60 | + | 3 10 | x | − | 1 5 | × | 300 | + | 1 5 | x |
| = | 60 | + | 3 10 | x | − | 60 | + | 1 5 | x |
| = | 0 | + | 1 2 | x |
| 0 | + | 1 2 | x | = | 300 | × | 9 | ÷ | 25 |
| Right side of the equation = | 108 |
| 0 | + | 1 2 | x | = | 108 |
| x | = | 108 | ÷ | 1 2 |
| = | 108 | × | 2 |
| x | = | 216 |