| ( | ( | L | × | 1 | − | 10 | ) | ÷ | 10 | ) | ÷ | ( | ( | 15 | − | 10 | ) | ÷ | 10 | ) | = | - | 1 |
| 方程两边同时乘以: | ( | ( | 15 | − | 10 | ) | ÷ | 10 | ) |
| ( | ( | L | × | 1 | − | 10 | ) | ÷ | 10 | ) | = | - | 1 | ( | ( | 15 | − | 10 | ) | ÷ | 10 | ) |
| ( | L | × | 1 | − | 10 | ) | ÷ | 10 | = | - | 1 | ( | ( | 15 | − | 10 | ) | ÷ | 10 | ) |
| ( | L | × | 1 | − | 10 | ) | ÷ | 10 | = | - | 1 | ( | 15 | − | 10 | ) | ÷ | 10 |
| ( | L | × | 1 | − | 10 | ) | × | 1 10 | = | - | 1 10 | ( | 15 | − | 10 | ) |
| L | × | 1 | × | 1 10 | − | 10 | × | 1 10 | = | - | 1 10 | ( | 15 | − | 10 | ) |
| L | × | 1 | × | 1 10 | − | 10 | × | 1 10 | = | - | 1 10 | × | 15 | + | 1 10 | × | 10 |
| L | × | 1 10 | − | 1 | = | - | 3 2 | + | 1 |
1 10 | L | − | 1 | = | - | 1 2 |
1 10 | L | = | - | 1 2 | + | 1 |
1 10 | L | = | 1 2 |
| L | = | 1 2 | ÷ | 1 10 |
| = | 1 2 | × | 10 |
| = | 1 | × | 5 |
| L | = | 5 |