| X | ÷ | ( | X | + | 100000 | ) | = | 421 1000 |
| 方程两边同时乘以: | ( | X | + | 100000 | ) |
| X | = | 421 1000 | ( | X | + | 100000 | ) |
| X | = | 421 1000 | X | + | 421 1000 | × | 100000 |
| X | = | 421 1000 | X | + | 42100 |
| X | − | 421 1000 | X | = | 42100 |
579 1000 | X | = | 42100 |
| X | = | 42100 | ÷ | 579 1000 |
| = | 42100 | × | 1000 579 |
| X | = | 42100000 579 |
| X | = | 72711.571675 |