| ( | 200000 | − | x | ) | ÷ | 400000 | = | 20 100 |
| Left side of the equation = | 200000 | × | 1 400000 | − | x | × | 1 400000 |
| = | 1 2 | − | x | × | 1 400000 |
1 2 | − | 1 400000 | x | = | 20 100 |
| - | 1 400000 | x | = | 20 100 | − | 1 2 |
| - | 1 400000 | x | = | - | 3 10 |
3 10 | = | 1 400000 | x |
1 400000 | x | = | 3 10 |
| x | = | 3 10 | ÷ | 1 400000 |
| = | 3 10 | × | 400000 |
| = | 3 | × | 40000 |
| x | = | 120000 |