| 3 | ÷ | 4 | × | x | + | 5 | ÷ | 6 | × | ( | 90 | − | x | ) | = | 70 |
| 方程左边 = | 3 4 | x | + | 5 6 | ( | 90 | − | x | ) |
3 4 | x | + | 5 6 | ( | 90 | − | x | ) | = | 70 |
| 方程左边 = | 3 4 | x | + | 5 6 | × | 90 | − | 5 6 | x |
| = | 3 4 | x | + | 75 | − | 5 6 | x |
| = | - | 1 12 | x | + | 75 |
| - | 1 12 | x | + | 75 | = | 70 |
| - | 1 12 | x | = | 70 | − | 75 |
| - | 1 12 | x | = | - | 5 |
| 5 | = | 1 12 | x |
1 12 | x | = | 5 |
| x | = | 5 | ÷ | 1 12 |
| = | 5 | × | 12 |
| x | = | 60 |