| 600 | × | 600 | + | ( | 8000 | − | x | ) | ( | 8000 | − | x | ) | = | 8000 | × | 8000 |
| 方程左边 = | 360000 | + | ( | 8000 | − | x | ) | ( | 8000 | − | x | ) |
| 360000 | + | ( | 8000 | − | x | ) | ( | 8000 | − | x | ) | = | 8000 | × | 8000 |
| 方程左边 = | 360000 | + | 8000 | ( | 8000 | − | x | ) | − | x | ( | 8000 | − | x | ) |
| = | 360000 | + | 8000 | × | 8000 | − | 8000 | x | − | x | ( | 8000 | − | x | ) |
| = | 360000 | + | 64000000 | − | 8000 | x | − | x | ( | 8000 | − | x | ) |
| = | 64360000 | − | 8000 | x | − | x | ( | 8000 | − | x | ) |
| = | 64360000 | − | 8000 | x | − | x | × | 8000 | + | x | x |
| = | 64360000 | − | 16000 | x | + | x | x |
| 64360000 | − | 16000 | x | + | x | x | = | 8000 | × | 8000 |
| 方程右边 = | 64000000 |
| 64360000 | − | 16000 | x | + | x | x | = | 64000000 |