| 5 | ÷ | 3 | × | x | + | 3 | ÷ | 5 | × | ( | 66 | − | x | ) | = | 78 |
| 方程左边 = | 5 3 | x | + | 3 5 | ( | 66 | − | x | ) |
5 3 | x | + | 3 5 | ( | 66 | − | x | ) | = | 78 |
| 方程左边 = | 5 3 | x | + | 3 5 | × | 66 | − | 3 5 | x |
| = | 5 3 | x | + | 198 5 | − | 3 5 | x |
| = | 16 15 | x | + | 198 5 |
16 15 | x | + | 198 5 | = | 78 |
16 15 | x | = | 78 | − | 198 5 |
16 15 | x | = | 192 5 |
| x | = | 192 5 | ÷ | 16 15 |
| = | 192 5 | × | 15 16 |
| = | 12 | × | 3 |
| x | = | 36 |