| ( | m | − | 5 | ) | ( | m | + | 10 | ) | = | ( | 1 | ÷ | 2 | ) | ( | m | + | 5 | ) |
| 方程左边 = | m | ( | m | + | 10 | ) | − | 5 | ( | m | + | 10 | ) |
| = | m | m | + | m | × | 10 | − | 5 | ( | m | + | 10 | ) |
| = | m | m | + | 10 | m | − | 5 | m | − | 5 | × | 10 |
| = | m | m | + | 10 | m | − | 5 | m | − | 50 |
| = | m | m | + | 5 | m | − | 50 |
| m | m | + | 5 | m | − | 50 | = | ( | 1 | ÷ | 2 | ) | ( | m | + | 5 | ) |
| 方程右边 = | 1 | ÷ | 2 | × | ( | m | + | 5 | ) |
| = | 1 2 | ( | m | + | 5 | ) |
| = | 1 2 | m | + | 1 2 | × | 5 |
| = | 1 2 | m | + | 5 2 |
| m | m | + | 5 | m | − | 50 | = | 1 2 | m | + | 5 2 |