| ( | 31 | × | 4 | + | 5 | x | ) | ÷ | ( | 31 | + | x | ) | = | 9 2 |
| 方程两边同时乘以: | ( | 31 | + | x | ) |
| ( | 31 | × | 4 | + | 5 | x | ) | = | 9 2 | ( | 31 | + | x | ) |
| 31 | × | 4 | + | 5 | x | = | 9 2 | ( | 31 | + | x | ) |
| 31 | × | 4 | + | 5 | x | = | 9 2 | × | 31 | + | 9 2 | x |
| 124 | + | 5 | x | = | 279 2 | + | 9 2 | x |
| 5 | x | − | 9 2 | x | = | 279 2 | − | 124 |
1 2 | x | = | 279 2 | − | 124 |
1 2 | x | = | 31 2 |
| x | = | 31 2 | ÷ | 1 2 |
| = | 31 2 | × | 2 |
| = | 31 | × | 1 |
| x | = | 31 |