| ( | 3 10 | − | 1 20 | x | ) | ( | 500 | + | 1 20 | x | ÷ | 200 | ) | = | 180 |
| Left side of the equation = | 3 10 | ( | 500 | + | 1 20 | x | ÷ | 200 | ) | − | 1 20 | x | ( | 500 | + | 1 20 | x | ÷ | 200 | ) |
| = | 3 10 | × | 500 | + | 3 10 | × | 1 20 | x | ÷ | 200 | − | 1 20 | x | ( | 500 | + | 1 20 | x | ÷ | 200 | ) |
| = | 150 | + | 3 40000 | x | − | 1 20 | x | ( | 500 | + | 1 20 | x | ÷ | 200 | ) |
| = | 150 | + | 3 40000 | x | − | 1 20 | x | × | 500 | − | 1 20 | x | × | 1 20 | x | ÷ | 200 |
| = | 150 | + | 3 40000 | x | − | 25 | x | − | 1 80000 | x | x |
| = | 150 | − | 999997 40000 | x | − | 1 80000 | x | x |
| 150 | − | 999997 40000 | x | − | 1 80000 | x | x | = | 180 |