| ( | 380 | − | 70 | ) | x | = | ( | 2580000 | + | 120 | ) | x |
| 方程左边 = | 380 | x | − | 70 | x |
| = | 310 | x |
| 310 | x | = | ( | 2580000 | + | 120 | ) | x |
| 方程右边 = | 2580000 | x | + | 120 | x |
| = | 2580120 | x |
| 310 | x | = | 2580120 | x |
| 310 | x | − | 2580120 | x | = | 0 |
| - | 2579810 | x | = | 0 |
| - | 0 | = | 2579810 | x |
| 2579810 | x | = | - | 0 |
| x | = | - | 0 | ÷ | 2579810 |
| = | - | 0 | × | 1 2579810 |
| x | = | 0 |