| ( | 360 | − | 30 | ( | x | − | 20 | ) | ) | ( | x | − | 16 | ) | = | 0 |
| 方程左边 = | 360 | ( | x | − | 16 | ) | − | 30 | ( | x | − | 20 | ) | ( | x | − | 16 | ) |
| = | 360 | x | − | 360 | × | 16 | − | 30 | ( | x | − | 20 | ) | ( | x | − | 16 | ) |
| = | 360 | x | − | 5760 | − | 30 | ( | x | − | 20 | ) | ( | x | − | 16 | ) |
| = | 360 | x | − | 5760 | − | 30 | x | ( | x | − | 16 | ) | + | 30 | × | 20 | ( | x | − | 16 | ) |
| = | 360 | x | − | 5760 | − | 30 | x | ( | x | − | 16 | ) | + | 600 | ( | x | − | 16 | ) |
| = | 360 | x | − | 5760 | − | 30 | x | x | + | 30 | x | × | 16 | + | 600 | ( | x | − | 16 | ) |
| = | 360 | x | − | 5760 | − | 30 | x | x | + | 480 | x | + | 600 | ( | x | − | 16 | ) |
| = | 840 | x | − | 5760 | − | 30 | x | x | + | 600 | ( | x | − | 16 | ) |
| = | 840 | x | − | 5760 | − | 30 | x | x | + | 600 | x | − | 600 | × | 16 |
| = | 840 | x | − | 5760 | − | 30 | x | x | + | 600 | x | − | 9600 |
| = | 1440 | x | − | 15360 | − | 30 | x | x |
| 1440 | x | − | 15360 | − | 30 | x | x | = | 0 |