| ( | 5 | ( | 18 | + | X | ) | + | 4 | × | 4 | + | 4 | × | 3 | + | 1 | × | 1 | ) | ÷ | ( | 27 | + | X | ) | = | 23 5 |
| 方程两边同时乘以: | ( | 27 | + | X | ) |
| ( | 5 | ( | 18 | + | X | ) | + | 4 | × | 4 | + | 4 | × | 3 | + | 1 | × | 1 | ) | = | 23 5 | ( | 27 | + | X | ) |
| 5 | ( | 18 | + | X | ) | + | 4 | × | 4 | + | 4 | × | 3 | + | 1 | × | 1 | = | 23 5 | ( | 27 | + | X | ) |
| 5 | ( | 18 | + | X | ) | + | 4 | × | 4 | + | 4 | × | 3 | + | 1 | × | 1 | = | 23 5 | × | 27 | + | 23 5 | X |
| 5 | ( | 18 | + | X | ) | + | 16 | + | 12 | + | 1 | = | 621 5 | + | 23 5 | X |
| 5 | ( | 18 | + | X | ) | + | 29 | = | 621 5 | + | 23 5 | X |
| 5 | × | 18 | + | 5 | X | + | 29 | = | 621 5 | + | 23 5 | X |
| 90 | + | 5 | X | + | 29 | = | 621 5 | + | 23 5 | X |
| 119 | + | 5 | X | = | 621 5 | + | 23 5 | X |
| 5 | X | − | 23 5 | X | = | 621 5 | − | 119 |
2 5 | X | = | 621 5 | − | 119 |
2 5 | X | = | 26 5 |
| X | = | 26 5 | ÷ | 2 5 |
| = | 26 5 | × | 5 2 |
| = | 13 | × | 1 |
| X | = | 13 |