| 20 | ( | 1 | ÷ | 40 | + | 1 | ÷ | x | ) | + | 20 | ( | 1 | ÷ | x | ) | = | 1 |
| 20 | × | 1 | ÷ | 40 | + | 20 | × | 1 | ÷ | x | + | 20 | ( | 1 | ÷ | x | ) | = | 1 |
1 2 | + | 20 | ÷ | x | + | 20 | ( | 1 | ÷ | x | ) | = | 1 |
| Multiply both sides of the equation by: | x |
1 2 | x | + | 20 | + | 20 | ( | 1 | ÷ | 1 | ) | × | 1 | = | 1 | x |
1 2 | x | + | 20 | + | 20 | × | 1 | ÷ | 1 | × | 1 | = | 1 | x |
1 2 | x | + | 20 | + | 20 | = | 1 | x |
1 2 | x | + | 40 | = | 1 | x |
1 2 | x | − | 1 | x | = | - | 40 |
| - | 1 2 | x | = | - | 40 |
| 40 | = | 1 2 | x |
1 2 | x | = | 40 |
| x | = | 40 | ÷ | 1 2 |
| = | 40 | × | 2 |
| x | = | 80 |