| ( | 1702 | + | x | ) | ÷ | ( | 1940 | + | x | ) | = | 90 |
| Multiply both sides of the equation by: | ( | 1940 | + | x | ) |
| ( | 1702 | + | x | ) | = | 90 | ( | 1940 | + | x | ) |
| 1702 | + | x | = | 90 | ( | 1940 | + | x | ) |
| 1702 | + | x | = | 90 | × | 1940 | + | 90 | x |
| 1702 | + | x | = | 174600 | + | 90 | x |
| x | − | 90 | x | = | 174600 | − | 1702 |
| - | 89 | x | = | 174600 | − | 1702 |
| - | 89 | x | = | 172898 |
| - | 172898 | = | 89 | x |
| 89 | x | = | - | 172898 |
| x | = | - | 172898 | ÷ | 89 |
| = | - | 172898 | × | 1 89 |
| x | = | - | 172898 89 |
| x | = | - 1942.674157 |