| 5000000 | + | ( | 55224 | + | 1 100 | x | ) | × | 21 20 | = | x |
| 方程左边 = | 5000000 | + | 55224 | × | 21 20 | + | 1 100 | x | × | 21 20 |
| = | 5000000 | + | 289926 5 | + | 21 2000 | x |
| = | 25289926 5 | + | 21 2000 | x |
25289926 5 | + | 21 2000 | x | = | x |
21 2000 | x | − | x | = | - | 25289926 5 |
| - | 1979 2000 | x | = | - | 25289926 5 |
25289926 5 | = | 1979 2000 | x |
1979 2000 | x | = | 25289926 5 |
| x | = | 25289926 5 | ÷ | 1979 2000 |
| = | 25289926 5 | × | 2000 1979 |
| = | 25289926 | × | 400 1979 |
| x | = | 10115970400 1979 |