| - | 5 | ( | 8 | p | − | 8 | ) | = | - | 10 | − | 5 | ( | p | + | 4 | ) |
| 方程左边 = | - | 5 | × | 8 | p | + | 5 | × | 8 |
| = | - | 40 | p | + | 40 |
| - | 40 | p | + | 40 | = | - | 10 | − | 5 | ( | p | + | 4 | ) |
| 方程右边 = | - | 10 | − | 5 | p | − | 5 | × | 4 |
| = | - | 10 | − | 5 | p | − | 20 |
| = | - | 30 | − | 5 | p |
| - | 40 | p | + | 40 | = | - | 30 | − | 5 | p |
| - | 40 | p | + | 5 | p | = | - | 30 | − | 40 |
| - | 35 | p | = | - | 30 | − | 40 |
| - | 35 | p | = | - | 70 |
| 70 | = | 35 | p |
| 35 | p | = | 70 |
| p | = | 70 | ÷ | 35 |
| = | 70 | × | 1 35 |
| = | 2 | × | 1 |
| p | = | 2 |