| ( | x | + | 3 | ( | 1 | ÷ | 7 | ) | ) | + | 2 | x | = | 7 | ( | 1 | ÷ | 3 | ) |
| 方程左边 = | x | + | 3 | ( | 1 | ÷ | 7 | ) | + | 2 | x |
| = | 3 | x | + | 3 | ( | 1 | ÷ | 7 | ) |
| = | 3 | x | + | 3 | × | 1 | ÷ | 7 |
| = | 3 | x | + | 3 7 |
| 3 | x | + | 3 7 | = | 7 | ( | 1 | ÷ | 3 | ) |
| 方程右边 = | 7 | × | 1 | ÷ | 3 |
| = | 7 3 |
| 3 | x | + | 3 7 | = | 7 3 |
| 3 | x | = | 7 3 | − | 3 7 |
| 3 | x | = | 40 21 |
| x | = | 40 21 | ÷ | 3 |
| = | 40 21 | × | 1 3 |
| x | = | 40 63 |
| x | = | 0.634921 |