| ( | 417 | + | x | ) | ÷ | ( | 1230 | + | x | ) | = | 7 20 |
| Multiply both sides of the equation by: | ( | 1230 | + | x | ) |
| ( | 417 | + | x | ) | = | 7 20 | ( | 1230 | + | x | ) |
| 417 | + | x | = | 7 20 | ( | 1230 | + | x | ) |
| 417 | + | x | = | 7 20 | × | 1230 | + | 7 20 | x |
| 417 | + | x | = | 861 2 | + | 7 20 | x |
| x | − | 7 20 | x | = | 861 2 | − | 417 |
13 20 | x | = | 861 2 | − | 417 |
13 20 | x | = | 27 2 |
| x | = | 27 2 | ÷ | 13 20 |
| = | 27 2 | × | 20 13 |
| = | 27 | × | 10 13 |
| x | = | 270 13 |
| x | = | 20.769231 |