| ( | x | − | 60 | ) | ( | - | x | + | 100 | ) | = | ( | x | − | 75 | ) | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| 方程左边 = | x | ( | - | x | + | 100 | ) | − | 60 | ( | - | x | + | 100 | ) |
| = | - | x | x | + | x | × | 100 | − | 60 | ( | - | x | + | 100 | ) |
| = | - | x | x | + | 100 | x | + | 60 | x | − | 60 | × | 100 |
| = | - | x | x | + | 100 | x | + | 60 | x | − | 6000 |
| = | - | x | x | + | 160 | x | − | 6000 |
| - | x | x | + | 160 | x | − | 6000 | = | ( | x | − | 75 | ) | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| 方程右边 = | x | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) | − | 75 | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| = | - | x | × | 2 | ( | x | − | 25 | ) | + | x | × | 150 | − | 75 | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| = | - | x | × | 2 | x | + | x | × | 2 | × | 25 | + | 150 | x | − | 75 | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| = | - | x | × | 2 | x | + | x | × | 50 | + | 150 | x | − | 75 | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| = | - | x | × | 2 | x | + | 200 | x | − | 75 | ( | - | 2 | ( | x | − | 25 | ) | + | 150 | ) |
| = | - | x | × | 2 | x | + | 200 | x | + | 75 | × | 2 | ( | x | − | 25 | ) | − | 75 | × | 150 |
| = | - | x | × | 2 | x | + | 200 | x | + | 150 | ( | x | − | 25 | ) | − | 11250 |
| = | - | x | × | 2 | x | + | 200 | x | + | 150 | x | − | 150 | × | 25 | − | 11250 |
| = | - | x | × | 2 | x | + | 200 | x | + | 150 | x | − | 3750 | − | 11250 |
| = | - | x | × | 2 | x | + | 350 | x | − | 15000 |
| - | x | x | + | 160 | x | − | 6000 | = | - | x | × | 2 | x | + | 350 | x | − | 15000 |