| ( | 10 | ÷ | 13 | − | x | ) | ( | 10 | ÷ | 13 | − | x | ) | = | x |
| 方程左边 = | 10 | ÷ | 13 | × | ( | 10 | ÷ | 13 | − | x | ) | − | x | ( | 10 | ÷ | 13 | − | x | ) |
| = | 10 13 | ( | 10 | ÷ | 13 | − | x | ) | − | x | ( | 10 | ÷ | 13 | − | x | ) |
| = | 10 13 | × | 10 | ÷ | 13 | − | 10 13 | x | − | x | ( | 10 | ÷ | 13 | − | x | ) |
| = | 100 169 | − | 10 13 | x | − | x | ( | 10 | ÷ | 13 | − | x | ) |
| = | 100 169 | − | 10 13 | x | − | x | × | 10 | ÷ | 13 | + | x | x |
| = | 100 169 | − | 10 13 | x | − | x | × | 10 13 | + | x | x |
| = | 100 169 | − | 20 13 | x | + | x | x |
100 169 | − | 20 13 | x | + | x | x | = | x |