| ( | 1 5 | x | + | 60 | ) | − | ( | 1 | ÷ | 4 | × | x | − | 60 | ) | = | 220 |
| Left side of the equation = | 1 5 | x | + | 60 | − | ( | 1 | ÷ | 4 | × | x | − | 60 | ) |
| = | 1 5 | x | + | 60 | − | 1 | ÷ | 4 | × | x | + | 60 |
| = | 1 5 | x | + | 60 | − | 1 4 | x | + | 60 |
| = | - | 1 20 | x | + | 120 |
| - | 1 20 | x | + | 120 | = | 220 |
| - | 1 20 | x | = | 220 | − | 120 |
| - | 1 20 | x | = | 100 |
| - | 100 | = | 1 20 | x |
1 20 | x | = | - | 100 |
| x | = | - | 100 | ÷ | 1 20 |
| = | - | 100 | × | 20 |
| x | = | - | 2000 |