| ( | 1 | + | 20 100 | ) | x | × | 90 100 | − | 50 | = | x | + | 120 |
| Left side of the equation = | 1 | x | × | 90 100 | + | 20 100 | x | × | 90 100 | − | 50 |
| = | 9 10 | x | + | 9 50 | x | − | 50 |
| = | 27 25 | x | − | 50 |
27 25 | x | − | 50 | = | x | + | 120 |
27 25 | x | − | x | = | 120 | + | 50 |
2 25 | x | = | 120 | + | 50 |
2 25 | x | = | 170 |
| x | = | 170 | ÷ | 2 25 |
| = | 170 | × | 25 2 |
| = | 85 | × | 25 |
| x | = | 2125 |