| ( | 50000 | ( | 1 | + | 887 10000 | ) | + | y | ) | × | 12 100 | = | 50000 | × | 887 10000 | + | 2000 |
| 方程左边 = | 50000 | ( | 1 | + | 887 10000 | ) | × | 12 100 | + | y | × | 12 100 |
| = | 6000 | ( | 1 | + | 887 10000 | ) | + | y | × | 12 100 |
| = | 6000 | × | 1 | + | 6000 | × | 887 10000 | + | 12 100 | y |
| = | 6000 | + | 2661 5 | + | 12 100 | y |
| = | 32661 5 | + | 12 100 | y |
32661 5 | + | 12 100 | y | = | 50000 | × | 887 10000 | + | 2000 |
| 方程右边 = | 4435 | + | 2000 |
| = | 6435 |
32661 5 | + | 12 100 | y | = | 6435 |
12 100 | y | = | 6435 | − | 32661 5 |
12 100 | y | = | - | 486 5 |
| y | = | - | 486 5 | ÷ | 12 100 |
| = | - | 486 5 | × | 100 12 |
| = | - | 81 | × | 20 2 |
| y | = | - | 1620 2 |
| y | = | - | 810 |