| X | ÷ | 45 | + | 3 50 | = | ( | X | + | 5 | ) | ÷ | ( | 45 | + | 5 | ) |
| 方程两边同时乘以: | ( | 45 | + | 5 | ) |
| X | ÷ | 45 | × | ( | 45 | + | 5 | ) | + | 3 50 | ( | 45 | + | 5 | ) | = | ( | X | + | 5 | ) |
| X | ÷ | 45 | × | 45 | + | X | ÷ | 45 | × | 5 | + | 3 50 | ( | 45 | + | 5 | ) | = | ( | X | + | 5 | ) |
| X | ÷ | 45 | × | 45 | + | X | ÷ | 45 | × | 5 | + | 3 50 | ( | 45 | + | 5 | ) | = | X | + | 5 |
| X | × | 1 | + | X | × | 1 9 | + | 3 50 | ( | 45 | + | 5 | ) | = | X | + | 5 |
10 9 | X | + | 3 50 | ( | 45 | + | 5 | ) | = | X | + | 5 |
10 9 | X | + | 3 50 | × | 45 | + | 3 50 | × | 5 | = | X | + | 5 |
10 9 | X | + | 27 10 | + | 3 10 | = | X | + | 5 |
10 9 | X | + | 3 | = | X | + | 5 |
10 9 | X | − | X | = | 5 | − | 3 |
1 9 | X | = | 5 | − | 3 |
1 9 | X | = | 2 |
| X | = | 2 | ÷ | 1 9 |
| = | 2 | × | 9 |
| X | = | 18 |