10 100 | x | + | 120 | × | 30 100 | = | 20 100 | ( | 120 | + | x | ) |
| 方程左边 = | 10 100 | x | + | 36 |
10 100 | x | + | 36 | = | 20 100 | ( | 120 | + | x | ) |
| 方程右边 = | 20 100 | × | 120 | + | 20 100 | x |
| = | 24 | + | 20 100 | x |
10 100 | x | + | 36 | = | 24 | + | 20 100 | x |
10 100 | x | − | 20 100 | x | = | 24 | − | 36 |
| - | 1 10 | x | = | 24 | − | 36 |
| - | 1 10 | x | = | - | 12 |
| 12 | = | 1 10 | x |
1 10 | x | = | 12 |
| x | = | 12 | ÷ | 1 10 |
| = | 12 | × | 10 |
| x | = | 120 |