| ( | 50000 | ( | 1 | + | 431 10000 | ) | + | y | ) | × | 12 100 | = | 50000 | × | 431 10000 | + | 2000 |
| 方程左边 = | 50000 | ( | 1 | + | 431 10000 | ) | × | 12 100 | + | y | × | 12 100 |
| = | 6000 | ( | 1 | + | 431 10000 | ) | + | y | × | 12 100 |
| = | 6000 | × | 1 | + | 6000 | × | 431 10000 | + | 12 100 | y |
| = | 6000 | + | 1293 5 | + | 12 100 | y |
| = | 31293 5 | + | 12 100 | y |
31293 5 | + | 12 100 | y | = | 50000 | × | 431 10000 | + | 2000 |
| 方程右边 = | 2155 | + | 2000 |
| = | 4155 |
31293 5 | + | 12 100 | y | = | 4155 |
12 100 | y | = | 4155 | − | 31293 5 |
12 100 | y | = | - | 10518 5 |
| y | = | - | 10518 5 | ÷ | 12 100 |
| = | - | 10518 5 | × | 100 12 |
| = | - | 1753 | × | 20 2 |
| y | = | - | 35060 2 |
| y | = | - | 17530 |