| ( | 5 | x | + | 40 | ) | ÷ | ( | x | + | 13 | ) | = | 49 10 |
| 方程两边同时乘以: | ( | x | + | 13 | ) |
| ( | 5 | x | + | 40 | ) | = | 49 10 | ( | x | + | 13 | ) |
| 5 | x | + | 40 | = | 49 10 | ( | x | + | 13 | ) |
| 5 | x | + | 40 | = | 49 10 | x | + | 49 10 | × | 13 |
| 5 | x | + | 40 | = | 49 10 | x | + | 637 10 |
| 5 | x | − | 49 10 | x | = | 637 10 | − | 40 |
1 10 | x | = | 637 10 | − | 40 |
1 10 | x | = | 237 10 |
| x | = | 237 10 | ÷ | 1 10 |
| = | 237 10 | × | 10 |
| = | 237 | × | 1 |
| x | = | 237 |