| 3 | ( | 20 | − | y | ) | = | 6 | y | − | 4 | ( | y | − | 11 | ) |
| 方程左边 = | 3 | × | 20 | − | 3 | y |
| = | 60 | − | 3 | y |
| 60 | − | 3 | y | = | 6 | y | − | 4 | ( | y | − | 11 | ) |
| 方程右边 = | 6 | y | − | 4 | y | + | 4 | × | 11 |
| = | 6 | y | − | 4 | y | + | 44 |
| = | 2 | y | + | 44 |
| 60 | − | 3 | y | = | 2 | y | + | 44 |
| - | 3 | y | − | 2 | y | = | 44 | − | 60 |
| - | 5 | y | = | 44 | − | 60 |
| - | 5 | y | = | - | 16 |
| 16 | = | 5 | y |
| 5 | y | = | 16 |
| y | = | 16 | ÷ | 5 |
| = | 16 | × | 1 5 |
| y | = | 16 5 |
| y | = | 3.2 |