| ( | 50000 | ( | 1 | + | 12 100 | ) | + | y | ) | × | 12 100 | = | 50000 | × | 12 100 |
| 方程左边 = | 50000 | ( | 1 | + | 12 100 | ) | × | 12 100 | + | y | × | 12 100 |
| = | 6000 | ( | 1 | + | 12 100 | ) | + | y | × | 12 100 |
| = | 6000 | × | 1 | + | 6000 | × | 12 100 | + | 12 100 | y |
| = | 6000 | + | 720 | + | 12 100 | y |
| = | 6720 | + | 12 100 | y |
| 6720 | + | 12 100 | y | = | 50000 | × | 12 100 |
| 方程右边 = | 6000 |
| 6720 | + | 12 100 | y | = | 6000 |
12 100 | y | = | 6000 | − | 6720 |
12 100 | y | = | - | 720 |
| y | = | - | 720 | ÷ | 12 100 |
| = | - | 720 | × | 100 12 |
| = | - | 60 | × | 100 |
| y | = | - | 6000 |