| ( | 4120 | + | 90 | x | ) | ÷ | ( | 97 2 | + | x | ) | = | 438 5 |
| 方程两边同时乘以: | ( | 97 2 | + | x | ) |
| ( | 4120 | + | 90 | x | ) | = | 438 5 | ( | 97 2 | + | x | ) |
| 4120 | + | 90 | x | = | 438 5 | ( | 97 2 | + | x | ) |
| 4120 | + | 90 | x | = | 438 5 | × | 97 2 | + | 438 5 | x |
| 4120 | + | 90 | x | = | 21243 5 | + | 438 5 | x |
| 90 | x | − | 438 5 | x | = | 21243 5 | − | 4120 |
12 5 | x | = | 21243 5 | − | 4120 |
12 5 | x | = | 643 5 |
| x | = | 643 5 | ÷ | 12 5 |
| = | 643 5 | × | 5 12 |
| = | 643 | × | 1 12 |
| x | = | 643 12 |
| x | = | 53.583333 |