| ( | 5 | ( | 10 | + | X | ) | + | 11 | ) | ÷ | ( | 15 | + | X | ) | = | 23 5 |
| Multiply both sides of the equation by: | ( | 15 | + | X | ) |
| ( | 5 | ( | 10 | + | X | ) | + | 11 | ) | = | 23 5 | ( | 15 | + | X | ) |
| 5 | ( | 10 | + | X | ) | + | 11 | = | 23 5 | ( | 15 | + | X | ) |
| 5 | ( | 10 | + | X | ) | + | 11 | = | 23 5 | × | 15 | + | 23 5 | X |
| 5 | ( | 10 | + | X | ) | + | 11 | = | 69 | + | 23 5 | X |
| 5 | × | 10 | + | 5 | X | + | 11 | = | 69 | + | 23 5 | X |
| 50 | + | 5 | X | + | 11 | = | 69 | + | 23 5 | X |
| 61 | + | 5 | X | = | 69 | + | 23 5 | X |
| 5 | X | − | 23 5 | X | = | 69 | − | 61 |
2 5 | X | = | 69 | − | 61 |
2 5 | X | = | 8 |
| X | = | 8 | ÷ | 2 5 |
| = | 8 | × | 5 2 |
| = | 4 | × | 5 |
| X | = | 20 |