| ( | n | − | 1 | ) | ÷ | ( | n | + | 1 | ) | = | 3 |
| Multiply both sides of the equation by: | ( | n | + | 1 | ) |
| ( | n | − | 1 | ) | = | 3 | ( | n | + | 1 | ) |
| n | − | 1 | = | 3 | ( | n | + | 1 | ) |
| n | − | 1 | = | 3 | n | + | 3 | × | 1 |
| n | − | 1 | = | 3 | n | + | 3 |
| n | − | 3 | n | = | 3 | + | 1 |
| - | 2 | n | = | 3 | + | 1 |
| - | 2 | n | = | 4 |
| - | 4 | = | 2 | n |
| 2 | n | = | - | 4 |
| n | = | - | 4 | ÷ | 2 |
| = | - | 4 | × | 1 2 |
| = | - | 2 | × | 1 |
| n | = | - | 2 |