| ( | x | − | 800 | × | 1 10 | ) | ( | 1 | − | 1 5 | ) | ÷ | 1600 | = | ( | x | − | 800 | × | 1 10 | − | 1600 | × | 3 20 | ) | ( | 1 | − | 1 5 | ) | ÷ | 1200 |
| 方程左边 = | x | ( | 1 | − | 1 5 | ) | × | 1 1600 | − | 800 | × | 1 10 | ( | 1 | − | 1 5 | ) | × | 1 1600 |
| = | x | ( | 1 | − | 1 5 | ) | × | 1 1600 | − | 1 20 | ( | 1 | − | 1 5 | ) |
| = | x | × | 1 | × | 1 1600 | − | x | × | 1 5 | × | 1 1600 | − | 1 20 | ( | 1 | − | 1 5 | ) |
| = | x | × | 1 1600 | − | x | × | 1 8000 | − | 1 20 | ( | 1 | − | 1 5 | ) |
| = | 1 2000 | x | − | 1 20 | ( | 1 | − | 1 5 | ) |
| = | 1 2000 | x | − | 1 20 | × | 1 | + | 1 20 | × | 1 5 |
| = | 1 2000 | x | − | 1 20 | + | 1 100 |
| = | 1 2000 | x | − | 1 25 |
1 2000 | x | − | 1 25 | = | ( | x | − | 800 | × | 1 10 | − | 1600 | × | 3 20 | ) | ( | 1 | − | 1 5 | ) | ÷ | 1200 |
| 方程右边 = | x | ( | 1 | − | 1 5 | ) | × | 1 1200 | − | 800 | × | 1 10 | ( | 1 | − | 1 5 | ) | × | 1 1200 | − | 1600 | × | 3 20 | ( | 1 | − | 1 5 | ) | × | 1 1200 |
| = | x | ( | 1 | − | 1 5 | ) | × | 1 1200 | − | 1 15 | ( | 1 | − | 1 5 | ) | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | x | × | 1 | × | 1 1200 | − | x | × | 1 5 | × | 1 1200 | − | 1 15 | ( | 1 | − | 1 5 | ) | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | x | × | 1 1200 | − | x | × | 1 6000 | − | 1 15 | ( | 1 | − | 1 5 | ) | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | 1 1500 | x | − | 1 15 | ( | 1 | − | 1 5 | ) | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | 1 1500 | x | − | 1 15 | × | 1 | + | 1 15 | × | 1 5 | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | 1 1500 | x | − | 1 15 | + | 1 75 | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | 1 1500 | x | − | 4 75 | − | 1 5 | ( | 1 | − | 1 5 | ) |
| = | 1 1500 | x | − | 4 75 | − | 1 5 | × | 1 | + | 1 5 | × | 1 5 |
| = | 1 1500 | x | − | 4 75 | − | 1 5 | + | 1 25 |
| = | 1 1500 | x | − | 16 75 |
1 2000 | x | − | 1 25 | = | 1 1500 | x | − | 16 75 |
1 2000 | x | − | 1 1500 | x | = | - | 16 75 | + | 1 25 |
| - | 1 6000 | x | = | - | 16 75 | + | 1 25 |
| - | 1 6000 | x | = | - | 13 75 |
13 75 | = | 1 6000 | x |
1 6000 | x | = | 13 75 |
| x | = | 13 75 | ÷ | 1 6000 |
| = | 13 75 | × | 6000 |
| = | 13 | × | 80 |
| x | = | 1040 |