| 17 | + | n | = | 3 | ( | 2 | ( | 7 | − | 4 | n | ) | + | 5 | n | ) |
| 方程右边 = | 3 | × | 2 | ( | 7 | − | 4 | n | ) | + | 3 | × | 5 | n |
| = | 6 | ( | 7 | − | 4 | n | ) | + | 15 | n |
| = | 6 | × | 7 | − | 6 | × | 4 | n | + | 15 | n |
| = | 42 | − | 24 | n | + | 15 | n |
| = | 42 | − | 9 | n |
| 17 | + | n | = | 42 | − | 9 | n |
| n | + | 9 | n | = | 42 | − | 17 |
| 10 | n | = | 42 | − | 17 |
| 10 | n | = | 25 |
| n | = | 25 | ÷ | 10 |
| = | 25 | × | 1 10 |
| = | 5 | × | 1 2 |
| n | = | 5 2 |
| n | = | 2.5 |