| ( | 206 | + | x | ) | ÷ | 7 | = | x | − | 30 |
| 方程左边 = | 206 | × | 1 7 | + | x | × | 1 7 |
| = | 206 7 | + | x | × | 1 7 |
206 7 | + | 1 7 | x | = | x | − | 30 |
1 7 | x | − | x | = | - | 30 | − | 206 7 |
| - | 6 7 | x | = | - | 30 | − | 206 7 |
| - | 6 7 | x | = | - | 416 7 |
416 7 | = | 6 7 | x |
6 7 | x | = | 416 7 |
| x | = | 416 7 | ÷ | 6 7 |
| = | 416 7 | × | 7 6 |
| = | 208 | × | 1 3 |
| x | = | 208 3 |
| x | = | 69.333333 |