| ( | 80 | − | 50 | ) | × | 40 | + | ( | 60 | − | x | ( | 80 | ( | 1 | + | 25 100 | ) | − | 80 | ) | ) | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) | = | 2200 |
| 方程左边 = | 80 | × | 40 | − | 50 | × | 40 | + | ( | 60 | − | x | ( | 80 | ( | 1 | + | 25 100 | ) | − | 80 | ) | ) | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 3200 | − | 2000 | + | ( | 60 | − | x | ( | 80 | ( | 1 | + | 25 100 | ) | − | 80 | ) | ) | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1200 | + | ( | 60 | − | x | ( | 80 | ( | 1 | + | 25 100 | ) | − | 80 | ) | ) | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1200 | + | 60 | − | x | ( | 80 | ( | 1 | + | 25 100 | ) | − | 80 | ) | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1260 | − | x | ( | 80 | ( | 1 | + | 25 100 | ) | − | 80 | ) | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1260 | − | x | × | 80 | ( | 1 | + | 25 100 | ) | + | x | × | 80 | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1260 | − | x | × | 80 | × | 1 | − | x | × | 80 | × | 25 100 | + | 80 | x | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1260 | − | x | × | 80 | − | x | × | 20 | + | 80 | x | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1260 | − | 20 | x | + | x | ( | 9 10 | ( | 80 | × | 125 100 | ) | − | 80 | ) |
| = | 1260 | − | 20 | x | + | x | × | 9 10 | ( | 80 | × | 125 100 | ) | − | x | × | 80 |
| = | 1260 | − | 100 | x | + | x | × | 9 10 | ( | 80 | × | 125 100 | ) |
| = | 1260 | − | 100 | x | + | x | × | 9 10 | × | 80 | × | 125 100 |
| = | 1260 | − | 100 | x | + | x | × | 90 |
| = | 1260 | − | 10 | x |
| 1260 | − | 10 | x | = | 2200 |
| - | 10 | x | = | 2200 | − | 1260 |
| - | 10 | x | = | 940 |
| - | 940 | = | 10 | x |
| 10 | x | = | - | 940 |
| x | = | - | 940 | ÷ | 10 |
| = | - | 940 | × | 1 10 |
| = | - | 94 | × | 1 |
| x | = | - | 94 |