| x | ÷ | 2 | + | 10 | + | ( | x | − | ( | x | ÷ | 2 | + | 10 | ) | ) | ÷ | 2 | + | 20 | + | 80 | = | x |
| Left side of the equation = | 1 2 | x | + | 110 | + | ( | x | − | ( | x | ÷ | 2 | + | 10 | ) | ) | × | 1 2 |
1 2 | x | + | 110 | + | ( | x | − | ( | x | ÷ | 2 | + | 10 | ) | ) | × | 1 2 | = | x |
| Left side of the equation = | 1 2 | x | + | 110 | + | x | × | 1 2 | − | ( | x | ÷ | 2 | + | 10 | ) | × | 1 2 |
| = | 1 | x | + | 110 | − | ( | x | ÷ | 2 | + | 10 | ) | × | 1 2 |
| = | 1 | x | + | 110 | − | x | ÷ | 2 | × | 1 2 | − | 10 | × | 1 2 |
| = | 1 | x | + | 110 | − | x | × | 1 4 | − | 5 |
| = | 3 4 | x | + | 105 |
3 4 | x | + | 105 | = | x |
3 4 | x | − | x | = | - | 105 |
| - | 1 4 | x | = | - | 105 |
| 105 | = | 1 4 | x |
1 4 | x | = | 105 |
| x | = | 105 | ÷ | 1 4 |
| = | 105 | × | 4 |
| x | = | 420 |