| ( | 28 | + | x | ) | ÷ | ( | 71 | + | x | ) | = | 3 5 |
| Multiply both sides of the equation by: | ( | 71 | + | x | ) |
| ( | 28 | + | x | ) | = | 3 5 | ( | 71 | + | x | ) |
| 28 | + | x | = | 3 5 | ( | 71 | + | x | ) |
| 28 | + | x | = | 3 5 | × | 71 | + | 3 5 | x |
| 28 | + | x | = | 213 5 | + | 3 5 | x |
| x | − | 3 5 | x | = | 213 5 | − | 28 |
2 5 | x | = | 213 5 | − | 28 |
2 5 | x | = | 73 5 |
| x | = | 73 5 | ÷ | 2 5 |
| = | 73 5 | × | 5 2 |
| = | 73 | × | 1 2 |
| x | = | 73 2 |
| x | = | 36.5 |