| 45 | x | + | 50 | ( | 102 | − | x | ) | = | 102 | × | 40 | + | 730 |
| 方程左边 = | 45 | x | + | 50 | × | 102 | − | 50 | x |
| = | 45 | x | + | 5100 | − | 50 | x |
| = | - | 5 | x | + | 5100 |
| - | 5 | x | + | 5100 | = | 102 | × | 40 | + | 730 |
| 方程右边 = | 4080 | + | 730 |
| = | 4810 |
| - | 5 | x | + | 5100 | = | 4810 |
| - | 5 | x | = | 4810 | − | 5100 |
| - | 5 | x | = | - | 290 |
| 290 | = | 5 | x |
| 5 | x | = | 290 |
| x | = | 290 | ÷ | 5 |
| = | 290 | × | 1 5 |
| = | 58 | × | 1 |
| x | = | 58 |