| ( | 53 | − | x | ) | × | 60 | = | ( | 45 | − | x | ) | × | 75 |
| 方程左边 = | 53 | × | 60 | − | x | × | 60 |
| = | 3180 | − | x | × | 60 |
| 3180 | − | 60 | x | = | ( | 45 | − | x | ) | × | 75 |
| 方程右边 = | 45 | × | 75 | − | x | × | 75 |
| = | 3375 | − | x | × | 75 |
| 3180 | − | 60 | x | = | 3375 | − | 75 | x |
| - | 60 | x | + | 75 | x | = | 3375 | − | 3180 |
| 15 | x | = | 3375 | − | 3180 |
| 15 | x | = | 195 |
| x | = | 195 | ÷ | 15 |
| = | 195 | × | 1 15 |
| = | 13 | × | 1 |
| x | = | 13 |