| ( | 35 | − | x | ) | ( | 23 | − | x | ) | = | 4 | ÷ | 5 | × | 23 | × | 35 |
| 方程左边 = | 35 | ( | 23 | − | x | ) | − | x | ( | 23 | − | x | ) |
| = | 35 | × | 23 | − | 35 | x | − | x | ( | 23 | − | x | ) |
| = | 805 | − | 35 | x | − | x | ( | 23 | − | x | ) |
| = | 805 | − | 35 | x | − | x | × | 23 | + | x | x |
| = | 805 | − | 58 | x | + | x | x |
| 805 | − | 58 | x | + | x | x | = | 4 | ÷ | 5 | × | 23 | × | 35 |
| 方程右边 = | 644 |
| 805 | − | 58 | x | + | x | x | = | 644 |