| ( | 3 | + | X | ) | ÷ | ( | 10 | + | X | ) | = | 12 25 |
| Multiply both sides of the equation by: | ( | 10 | + | X | ) |
| ( | 3 | + | X | ) | = | 12 25 | ( | 10 | + | X | ) |
| 3 | + | X | = | 12 25 | ( | 10 | + | X | ) |
| 3 | + | X | = | 12 25 | × | 10 | + | 12 25 | X |
| 3 | + | X | = | 24 5 | + | 12 25 | X |
| X | − | 12 25 | X | = | 24 5 | − | 3 |
13 25 | X | = | 24 5 | − | 3 |
13 25 | X | = | 9 5 |
| X | = | 9 5 | ÷ | 13 25 |
| = | 9 5 | × | 25 13 |
| = | 9 | × | 5 13 |
| X | = | 45 13 |
| X | = | 3.461538 |