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