| 3 | ÷ | 4 | × | x | + | 25 | = | 9 | ÷ | 10 | × | x | − | 20 |
| 方程左边 = | 3 4 | x | + | 25 |
3 4 | x | + | 25 | = | 9 | ÷ | 10 | × | x | − | 20 |
| 方程右边 = | 9 10 | x | − | 20 |
3 4 | x | + | 25 | = | 9 10 | x | − | 20 |
3 4 | x | − | 9 10 | x | = | - | 20 | − | 25 |
| - | 3 20 | x | = | - | 20 | − | 25 |
| - | 3 20 | x | = | - | 45 |
| 45 | = | 3 20 | x |
3 20 | x | = | 45 |
| x | = | 45 | ÷ | 3 20 |
| = | 45 | × | 20 3 |
| = | 15 | × | 20 |
| x | = | 300 |