| ( | 2621 5 | − | y | ) | ÷ | y | = | 12 500 |
| 方程两边同时乘以: | y |
| ( | 2621 5 | − | y | ) | = | 12 500 | y |
2621 5 | − | y | = | 12 500 | y |
| - | y | − | 12 500 | y | = | - | 2621 5 |
| - | 128 125 | y | = | - | 2621 5 |
2621 5 | = | 128 125 | y |
128 125 | y | = | 2621 5 |
| y | = | 2621 5 | ÷ | 128 125 |
| = | 2621 5 | × | 125 128 |
| = | 2621 | × | 25 128 |
| y | = | 65525 128 |
| y | = | 511.914062 |