| ( | 120 | + | 2 | x | ) | ( | 60 | + | 3 | ÷ | 2 | × | x | ) | = | 2 | × | 120 | × | 60 |
| 方程左边 = | 120 | ( | 60 | + | 3 | ÷ | 2 | × | x | ) | + | 2 | x | ( | 60 | + | 3 | ÷ | 2 | × | x | ) |
| = | 120 | × | 60 | + | 120 | × | 3 | ÷ | 2 | × | x | + | 2 | x | ( | 60 | + | 3 | ÷ | 2 | × | x | ) |
| = | 7200 | + | 180 | x | + | 2 | x | ( | 60 | + | 3 | ÷ | 2 | × | x | ) |
| = | 7200 | + | 180 | x | + | 2 | x | × | 60 | + | 2 | x | × | 3 | ÷ | 2 | × | x |
| = | 7200 | + | 180 | x | + | 120 | x | + | 3 | x | x |
| = | 7200 | + | 300 | x | + | 3 | x | x |
| 7200 | + | 300 | x | + | 3 | x | x | = | 2 | × | 120 | × | 60 |
| 方程右边 = | 14400 |
| 7200 | + | 300 | x | + | 3 | x | x | = | 14400 |