| ( | 3 | + | X | ) | ÷ | ( | 6 | + | X | ) | = | 9 10 |
| Multiply both sides of the equation by: | ( | 6 | + | X | ) |
| ( | 3 | + | X | ) | = | 9 10 | ( | 6 | + | X | ) |
| 3 | + | X | = | 9 10 | ( | 6 | + | X | ) |
| 3 | + | X | = | 9 10 | × | 6 | + | 9 10 | X |
| 3 | + | X | = | 27 5 | + | 9 10 | X |
| X | − | 9 10 | X | = | 27 5 | − | 3 |
1 10 | X | = | 27 5 | − | 3 |
1 10 | X | = | 12 5 |
| X | = | 12 5 | ÷ | 1 10 |
| = | 12 5 | × | 10 |
| = | 12 | × | 2 |
| X | = | 24 |