423 100 | X | + | 10 | ( | 20 | − | X | ) | = | 1000 |
| 方程左边 = | 423 100 | X | + | 10 | × | 20 | − | 10 | X |
| = | 423 100 | X | + | 200 | − | 10 | X |
| = | - | 577 100 | X | + | 200 |
| - | 577 100 | X | + | 200 | = | 1000 |
| - | 577 100 | X | = | 1000 | − | 200 |
| - | 577 100 | X | = | 800 |
| - | 800 | = | 577 100 | X |
577 100 | X | = | - | 800 |
| X | = | - | 800 | ÷ | 577 100 |
| = | - | 800 | × | 100 577 |
| X | = | - | 80000 577 |
| X | = | - 138.64818 |