| ( | 28623 10 | + | a | ) | ÷ | ( | 609 | + | a | ) | = | 4 |
| Multiply both sides of the equation by: | ( | 609 | + | a | ) |
| ( | 28623 10 | + | a | ) | = | 4 | ( | 609 | + | a | ) |
28623 10 | + | a | = | 4 | ( | 609 | + | a | ) |
28623 10 | + | a | = | 4 | × | 609 | + | 4 | a |
28623 10 | + | a | = | 2436 | + | 4 | a |
| a | − | 4 | a | = | 2436 | − | 28623 10 |
| - | 3 | a | = | 2436 | − | 28623 10 |
| - | 3 | a | = | - | 4263 10 |
4263 10 | = | 3 | a |
| 3 | a | = | 4263 10 |
| a | = | 4263 10 | ÷ | 3 |
| = | 4263 10 | × | 1 3 |
| = | 1421 10 | × | 1 |
| a | = | 1421 10 |
| a | = | 142.1 |