| 200 | ( | y | − | 8 | ) | + | 60 | ( | y | − | 10 | ) | = | 0 |
| 方程左边 = | 200 | y | − | 200 | × | 8 | + | 60 | ( | y | − | 10 | ) |
| = | 200 | y | − | 1600 | + | 60 | ( | y | − | 10 | ) |
| = | 200 | y | − | 1600 | + | 60 | y | − | 60 | × | 10 |
| = | 200 | y | − | 1600 | + | 60 | y | − | 600 |
| = | 260 | y | − | 2200 |
| 260 | y | − | 2200 | = | 0 |
| 260 | y | = | 0 | + | 2200 |
| 260 | y | = | 2200 |
| y | = | 2200 | ÷ | 260 |
| = | 2200 | × | 1 260 |
| = | 110 | × | 1 13 |
| y | = | 110 13 |
| y | = | 8.461538 |