| - | 1200 | + | ( | 40 | ( | 1 | + | x% | ) | × | 10 | − | 170 | ) | × | 28251 5000 | + | 100 | × | 161 500 | = | 0 |
| 方程左边 = | - | 1200 | + | ( | 40 | ( | 1 | + | x% | ) | × | 10 | − | 170 | ) | × | 28251 5000 | + | 161 5 |
| = | - | 5839 5 | + | ( | 40 | ( | 1 | + | x% | ) | × | 10 | − | 170 | ) | × | 28251 5000 |
| - | 5839 5 | + | ( | 40 | ( | 1 | + | x% | ) | × | 10 | − | 170 | ) | × | 28251 5000 | = | 0 |
| 方程左边 = | - | 5839 5 | + | 40 | ( | 1 | + | x% | ) | × | 10 | × | 28251 5000 | − | 170 | × | 28251 5000 |
| = | - | 5839 5 | + | 56502 25 | ( | 1 | + | x% | ) | − | 480267 500 |
| = | - | 1064167 500 | + | 56502 25 | ( | 1 | + | x% | ) |
| = | - | 1064167 500 | + | 56502 25 | × | 1 | + | 56502 25 | × | x% |
| = | - | 1064167 500 | + | 56502 25 | + | 28251 1250 | x |
| = | 65873 500 | + | 28251 1250 | x |
65873 500 | + | 28251 1250 | x | = | 0 |
28251 1250 | x | = | 0 | − | 65873 500 |
28251 1250 | x | = | - | 65873 500 |
| x | = | - | 65873 500 | ÷ | 28251 1250 |
| = | - | 65873 500 | × | 1250 28251 |
| = | - | 65873 2 | × | 5 28251 |
| x | = | - | 329365 56502 |
| x | = | - 5.829263 |