| ( | 1920 | + | x | ) | ÷ | ( | 3622 | + | x | ) | = | 13 20 |
| 方程两边同时乘以: | ( | 3622 | + | x | ) |
| ( | 1920 | + | x | ) | = | 13 20 | ( | 3622 | + | x | ) |
| 1920 | + | x | = | 13 20 | ( | 3622 | + | x | ) |
| 1920 | + | x | = | 13 20 | × | 3622 | + | 13 20 | x |
| 1920 | + | x | = | 23543 10 | + | 13 20 | x |
| x | − | 13 20 | x | = | 23543 10 | − | 1920 |
7 20 | x | = | 23543 10 | − | 1920 |
7 20 | x | = | 4343 10 |
| x | = | 4343 10 | ÷ | 7 20 |
| = | 4343 10 | × | 20 7 |
| = | 4343 | × | 2 7 |
| x | = | 8686 7 |
| x | = | 1240.857143 |