| 20 | + | 3 10 | x | = | ( | 1000 | + | x | − | 980 | ) | × | 50 100 |
| 方程右边 = | 1000 | × | 50 100 | + | x | × | 50 100 | − | 980 | × | 50 100 |
| = | 500 | + | x | × | 50 100 | − | 490 |
| = | 10 | + | 50 100 | x |
| 20 | + | 3 10 | x | = | 10 | + | 50 100 | x |
3 10 | x | − | 50 100 | x | = | 10 | − | 20 |
| - | 1 5 | x | = | 10 | − | 20 |
| - | 1 5 | x | = | - | 10 |
| 10 | = | 1 5 | x |
1 5 | x | = | 10 |
| x | = | 10 | ÷ | 1 5 |
| = | 10 | × | 5 |
| x | = | 50 |