| ( | ( | 3573 50 | + | 1847 100 | ) | ÷ | 2 | − | X | ) | ÷ | ( | 3573 50 | − | 1847 100 | ) | = | 9 20 |
| 方程两边同时乘以: | ( | 3573 50 | − | 1847 100 | ) |
| ( | ( | 3573 50 | + | 1847 100 | ) | ÷ | 2 | − | X | ) | = | 9 20 | ( | 3573 50 | − | 1847 100 | ) |
| ( | 3573 50 | + | 1847 100 | ) | ÷ | 2 | − | X | = | 9 20 | ( | 3573 50 | − | 1847 100 | ) |
| ( | 3573 50 | + | 1847 100 | ) | ÷ | 2 | − | X | = | 9 20 | × | 3573 50 | − | 9 20 | × | 1847 100 |
| ( | 3573 50 | + | 1847 100 | ) | × | 1 2 | − | X | = | 32157 1000 | − | 16623 2000 |
| ( | 3573 50 | + | 1847 100 | ) | × | 1 2 | − | X | = | 47691 2000 |
3573 50 | × | 1 2 | + | 1847 100 | × | 1 2 | − | X | = | 47691 2000 |
3573 100 | + | 1847 200 | − | X | = | 47691 2000 |
8993 200 | − | X | = | 47691 2000 |
| - | X | = | 47691 2000 | − | 8993 200 |
| - | X | = | - | 42239 2000 |
42239 2000 | = | X |
| X | = | 42239 2000 |