| ( | 10 | + | x | ) | ÷ | ( | 100 | − | x | ) | = | 1 5 |
| Multiply both sides of the equation by: | ( | 100 | − | x | ) |
| ( | 10 | + | x | ) | = | 1 5 | ( | 100 | − | x | ) |
| 10 | + | x | = | 1 5 | ( | 100 | − | x | ) |
| 10 | + | x | = | 1 5 | × | 100 | − | 1 5 | x |
| 10 | + | x | = | 20 | − | 1 5 | x |
| x | + | 1 5 | x | = | 20 | − | 10 |
6 5 | x | = | 20 | − | 10 |
6 5 | x | = | 10 |
| x | = | 10 | ÷ | 6 5 |
| = | 10 | × | 5 6 |
| = | 5 | × | 5 3 |
| x | = | 25 3 |
| x | = | 8.333333 |