| 2 | x | ÷ | 80 | + | 8 | ( | x | + | 5 | ) | ÷ | 80 | = | 3 | ÷ | 4 |
| 方程左边 = | 1 40 | x | + | 1 10 | ( | x | + | 5 | ) |
1 40 | x | + | 1 10 | ( | x | + | 5 | ) | = | 3 | ÷ | 4 |
| 方程左边 = | 1 40 | x | + | 1 10 | x | + | 1 10 | × | 5 |
| = | 1 40 | x | + | 1 10 | x | + | 1 2 |
| = | 1 8 | x | + | 1 2 |
1 8 | x | + | 1 2 | = | 3 | ÷ | 4 |
| 方程右边 = | 3 4 |
1 8 | x | + | 1 2 | = | 3 4 |
1 8 | x | = | 3 4 | − | 1 2 |
1 8 | x | = | 1 4 |
| x | = | 1 4 | ÷ | 1 8 |
| = | 1 4 | × | 8 |
| = | 1 | × | 2 |
| x | = | 2 |