25 100 | = | ( | 500000 | − | x | ) | ÷ | x | × | 100 100 |
| 方程两边同时乘以: | x |
25 100 | x | = | ( | 500000 | − | x | ) | × | 100 100 |
25 100 | x | = | 500000 | × | 100 100 | − | x | × | 100 100 |
25 100 | x | = | 500000 | − | x | × | 100 100 |
25 100 | x | + | 100 100 | x | = | 500000 |
5 4 | x | = | 500000 |
| x | = | 500000 | ÷ | 5 4 |
| = | 500000 | × | 4 5 |
| = | 100000 | × | 4 |
| x | = | 400000 |