| X | × | 45 | + | 3 50 | = | ( | X | + | 5 | ) | ( | 45 | + | 5 | ) |
| 方程右边 = | X | ( | 45 | + | 5 | ) | + | 5 | ( | 45 | + | 5 | ) |
| = | X | × | 45 | + | X | × | 5 | + | 5 | ( | 45 | + | 5 | ) |
| = | 50 | X | + | 5 | ( | 45 | + | 5 | ) |
| = | 50 | X | + | 5 | × | 45 | + | 5 | × | 5 |
| = | 50 | X | + | 225 | + | 25 |
| = | 50 | X | + | 250 |
| 45 | X | + | 3 50 | = | 50 | X | + | 250 |
| 45 | X | − | 50 | X | = | 250 | − | 3 50 |
| - | 5 | X | = | 250 | − | 3 50 |
| - | 5 | X | = | 12497 50 |
| - | 12497 50 | = | 5 | X |
| 5 | X | = | - | 12497 50 |
| X | = | - | 12497 50 | ÷ | 5 |
| = | - | 12497 50 | × | 1 5 |
| X | = | - | 12497 250 |
| X | = | - 49.988 |