| ( | 8 | + | x | ) | ÷ | ( | 11 | + | x | ) | = | 9 10 |
| Multiply both sides of the equation by: | ( | 11 | + | x | ) |
| ( | 8 | + | x | ) | = | 9 10 | ( | 11 | + | x | ) |
| 8 | + | x | = | 9 10 | ( | 11 | + | x | ) |
| 8 | + | x | = | 9 10 | × | 11 | + | 9 10 | x |
| 8 | + | x | = | 99 10 | + | 9 10 | x |
| x | − | 9 10 | x | = | 99 10 | − | 8 |
1 10 | x | = | 99 10 | − | 8 |
1 10 | x | = | 19 10 |
| x | = | 19 10 | ÷ | 1 10 |
| = | 19 10 | × | 10 |
| = | 19 | × | 1 |
| x | = | 19 |