| ( | 20 | + | 10 | ) | × | 9 | ÷ | 7 | − | ( | 1600 | × | 20 | + | 10 | x | ) | = | 8000 |
| 方程左边 = | ( | 20 | + | 10 | ) | × | 9 7 | − | ( | 1600 | × | 20 | + | 10 | x | ) |
| ( | 20 | + | 10 | ) | × | 9 7 | − | ( | 1600 | × | 20 | + | 10 | x | ) | = | 8000 |
| 方程左边 = | 20 | × | 9 7 | + | 10 | × | 9 7 | − | ( | 1600 | × | 20 | + | 10 | x | ) |
| = | 180 7 | + | 90 7 | − | ( | 1600 | × | 20 | + | 10 | x | ) |
| = | 270 7 | − | ( | 1600 | × | 20 | + | 10 | x | ) |
| = | 270 7 | − | 1600 | × | 20 | − | 10 | x |
| = | 270 7 | − | 32000 | − | 10 | x |
| = | - | 223730 7 | − | 10 | x |
| - | 223730 7 | − | 10 | x | = | 8000 |
| - | 10 | x | = | 8000 | + | 223730 7 |
| - | 10 | x | = | 279730 7 |
| - | 279730 7 | = | 10 | x |
| 10 | x | = | - | 279730 7 |
| x | = | - | 279730 7 | ÷ | 10 |
| = | - | 279730 7 | × | 1 10 |
| = | - | 27973 7 | × | 1 |
| x | = | - | 27973 7 |
| x | = | - 3996.142857 |