| ( | 500000 | ÷ | ( | n | + | 5 | ) | × | n | − | 40000 | ) | = | 0 |
| 500000 | ÷ | ( | n | + | 5 | ) | × | n | − | 40000 | = | 0 |
| 方程两边同时乘以: | ( | n | + | 5 | ) |
| 500000 | n | − | 40000 | ( | n | + | 5 | ) | = | 0 |
| 500000 | n | − | 40000 | n | − | 40000 | × | 5 | = | 0 |
| 500000 | n | − | 40000 | n | − | 200000 | = | 0 |
| 460000 | n | − | 200000 | = | 0 |
| 460000 | n | = | 0 | + | 200000 |
| 460000 | n | = | 200000 |
| n | = | 200000 | ÷ | 460000 |
| = | 200000 | × | 1 460000 |
| = | 10 | × | 1 23 |
| n | = | 10 23 |
| n | = | 0.434783 |