7 20 | = | 1 | ÷ | 2 | × | ( | x | ÷ | 21 | ) | − | 1 |
| Right side of the equation = | 1 2 | ( | x | ÷ | 21 | ) | − | 1 |
7 20 | = | 1 2 | ( | x | ÷ | 21 | ) | − | 1 |
| Right side of the equation = | 1 2 | x | ÷ | 21 | − | 1 |
| = | 1 42 | x | − | 1 |
7 20 | = | 1 42 | x | − | 1 |
| - | 1 42 | x | = | - | 1 | − | 7 20 |
| - | 1 42 | x | = | - | 27 20 |
27 20 | = | 1 42 | x |
1 42 | x | = | 27 20 |
| x | = | 27 20 | ÷ | 1 42 |
| = | 27 20 | × | 42 |
| = | 27 10 | × | 21 |
| x | = | 567 10 |
| x | = | 56.7 |