| 4 | ( | 2 | d | + | 5 | ) | + | 3 | ( | d | − | 2 | ) | = | 7 |
| Left side of the equation = | 4 | × | 2 | d | + | 4 | × | 5 | + | 3 | ( | d | − | 2 | ) |
| = | 8 | d | + | 20 | + | 3 | ( | d | − | 2 | ) |
| = | 8 | d | + | 20 | + | 3 | d | − | 3 | × | 2 |
| = | 8 | d | + | 20 | + | 3 | d | − | 6 |
| = | 11 | d | + | 14 |
| 11 | d | + | 14 | = | 7 |
| 11 | d | = | 7 | − | 14 |
| 11 | d | = | - | 7 |
| d | = | - | 7 | ÷ | 11 |
| = | - | 7 | × | 1 11 |
| d | = | - | 7 11 |
| d | = | - 0.636364 |