| 3 | x | − | 60 | − | 30 | = | 2 | ÷ | 3 | × | ( | x | + | 30 | ) |
| 方程左边 = | 3 | x | − | 90 |
| 3 | x | − | 90 | = | 2 | ÷ | 3 | × | ( | x | + | 30 | ) |
| 方程右边 = | 2 3 | ( | x | + | 30 | ) |
| 3 | x | − | 90 | = | 2 3 | ( | x | + | 30 | ) |
| 方程右边 = | 2 3 | x | + | 2 3 | × | 30 |
| = | 2 3 | x | + | 20 |
| 3 | x | − | 90 | = | 2 3 | x | + | 20 |
| 3 | x | − | 2 3 | x | = | 20 | + | 90 |
7 3 | x | = | 20 | + | 90 |
7 3 | x | = | 110 |
| x | = | 110 | ÷ | 7 3 |
| = | 110 | × | 3 7 |
| x | = | 330 7 |
| x | = | 47.142857 |