| ( | 160 | + | 120 | x | ) | ( | 16 | − | 3 | x | ) | = | 3640 |
| 方程左边 = | 160 | ( | 16 | − | 3 | x | ) | + | 120 | x | ( | 16 | − | 3 | x | ) |
| = | 160 | × | 16 | − | 160 | × | 3 | x | + | 120 | x | ( | 16 | − | 3 | x | ) |
| = | 2560 | − | 480 | x | + | 120 | x | ( | 16 | − | 3 | x | ) |
| = | 2560 | − | 480 | x | + | 120 | x | × | 16 | − | 120 | x | × | 3 | x |
| = | 2560 | − | 480 | x | + | 1920 | x | − | 360 | x | x |
| = | 2560 | + | 1440 | x | − | 360 | x | x |
| 2560 | + | 1440 | x | − | 360 | x | x | = | 3640 |