| y | ( | ( | - | 2 | ) | y | + | 8 | ) | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) | = | 0 |
| 方程左边 = | y | ( | - | 2 | ) | y | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) | + | y | × | 8 | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) |
| = | - | y | × | 2 | y | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) | + | y | × | 8 | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) |
| = | - | y | × | 2 | y | y | ( | - | 5 | ÷ | 3 | ) | + | y | × | 2 | y | × | 31 | ÷ | 10 | × | ( | - | 5 | ÷ | 3 | ) | + | y |
| = | - | y | × | 2 | y | y | ( | - | 5 | ÷ | 3 | ) | + | y | × | 31 5 | y | ( | - | 5 | ÷ | 3 | ) | + | y | × | 8 | ( | y | − | 31 | ÷ | 10 | ) |
| = | y | × | 2 | y | y | × | 5 | ÷ | 3 | + | y | × | 31 5 | y | ( | - | 5 | ÷ | 3 | ) | + | y | × | 8 |
| = | y | × | 10 3 | y | y | + | y | × | 31 5 | y | ( | - | 5 | ÷ | 3 | ) | + | y | × | 8 | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) |
| = | y | × | 10 3 | y | y | − | y | × | 31 5 | y | × | 5 | ÷ | 3 | + | y | × | 8 | ( | y | − | 31 | ÷ | 10 | ) |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | + | y | × | 8 | ( | y | − | 31 | ÷ | 10 | ) | ( | - | 5 | ÷ | 3 | ) |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | + | y | × | 8 | y | ( | - | 5 | ÷ | 3 | ) | − | y |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | + | y | × | 8 | y | ( | - | 5 | ÷ | 3 | ) | − | y |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | − | y | × | 8 | y | × | 5 | ÷ | 3 |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | − | y | × | 40 3 | y | − | y | × | 124 5 |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | − | y | × | 40 3 | y | + | y | × | 124 5 |
| = | y | × | 10 3 | y | y | − | y | × | 31 3 | y | − | y | × | 40 3 | y | + | y | × | 124 3 |
| y | × | 10 3 | y | y | − | y | × | 31 3 | y | − | y | × | 40 3 | y | + | 124 3 | y | = | 0 |
| y2= | 31 10 |
| y3=4 |