| 1 | + | ( | 139 50 | ( | x | + | 20 | ) | ) | ÷ | ( | x | + | 1420 | ) | = | 0 |
| 方程两边同时乘以: | ( | x | + | 1420 | ) |
| 1 | ( | x | + | 1420 | ) | + | ( | 139 50 | ( | x | + | 20 | ) | ) | = | 0 |
| 1 | x | + | 1 | × | 1420 | + | ( | 139 50 | ( | x | + | 20 | ) | ) | = | 0 |
| 1 | x | + | 1420 | + | ( | 139 50 | ( | x | + | 20 | ) | ) | = | 0 |
| 1 | x | + | 1420 | + | 139 50 | ( | x | + | 20 | ) | = | 0 |
| 1 | x | + | 1420 | + | 139 50 | x | + | 139 50 | × | 20 | = | 0 |
| 1 | x | + | 1420 | + | 139 50 | x | + | 278 5 | = | 0 |
189 50 | x | + | 7378 5 | = | 0 |
189 50 | x | = | 0 | − | 7378 5 |
189 50 | x | = | - | 7378 5 |
| x | = | - | 7378 5 | ÷ | 189 50 |
| = | - | 7378 5 | × | 50 189 |
| = | - | 1054 | × | 10 27 |
| x | = | - | 10540 27 |
| x | = | - 390.37037 |