| - | 2 | = | ( | x | − | 2780 | ) | ÷ | 2780 | × | 100 |
| 方程右边 = | ( | x | − | 2780 | ) | × | 5 139 |
| - | 2 | = | ( | x | − | 2780 | ) | × | 5 139 |
| 方程右边 = | x | × | 5 139 | − | 2780 | × | 5 139 |
| = | x | × | 5 139 | − | 100 |
| - | 2 | = | 5 139 | x | − | 100 |
| - | 5 139 | x | = | - | 100 | + | 2 |
| - | 5 139 | x | = | - | 98 |
| 98 | = | 5 139 | x |
5 139 | x | = | 98 |
| x | = | 98 | ÷ | 5 139 |
| = | 98 | × | 139 5 |
| x | = | 13622 5 |
| x | = | 2724.4 |