| 1 | ÷ | d | + | ( | 1 | ÷ | d | + | 3 | ) | + | ( | 1 | ÷ | d | + | 5 | ) | = | 0 |
| Multiply both sides of the equation by: | d |
| 1 | + | ( | 1 | ÷ | d | + | 3 | ) | d | + | ( | 1 | ÷ | d | + | 5 | ) | d | = | 0 |
| 1 | + | 1 | ÷ | d | × | d | + | 3 | d | + | ( | 1 | ÷ | d | + | 5 | ) | d | = | 0 |
| 1 | + | 1 | ÷ | 1 | × | 1 | + | 3 | d | + | 1 | ÷ | d | × | d | + | 5 | d | = | 0 |
| 1 | + | 1 | + | 3 | d | + | 1 | ÷ | d | × | d | + | 5 | d | = | 0 |
| 2 | + | 8 | d | + | 1 | ÷ | d | × | d | = | 0 |
| 8 | d | = | 0 | − | 2 | − | 1 | ÷ | 1 | × | 1 |
| 8 | d | = | 0 | − | 2 | − | 1 |
| 8 | d | = | - | 3 |
| d | = | - | 3 | ÷ | 8 |
| = | - | 3 | × | 1 8 |
| d | = | - | 3 8 |
| d | = | - 0.375 |