| 3 | x | ÷ | 5 | + | 5 | ( | 66 | − | x | ) | ÷ | 3 | = | 78 |
| Left side of the equation = | 3 5 | x | + | 5 3 | ( | 66 | − | x | ) |
3 5 | x | + | 5 3 | ( | 66 | − | x | ) | = | 78 |
| Left side of the equation = | 3 5 | x | + | 5 3 | × | 66 | − | 5 3 | x |
| = | 3 5 | x | + | 110 | − | 5 3 | x |
| = | - | 16 15 | x | + | 110 |
| - | 16 15 | x | + | 110 | = | 78 |
| - | 16 15 | x | = | 78 | − | 110 |
| - | 16 15 | x | = | - | 32 |
| 32 | = | 16 15 | x |
16 15 | x | = | 32 |
| x | = | 32 | ÷ | 16 15 |
| = | 32 | × | 15 16 |
| = | 2 | × | 15 |
| x | = | 30 |