| 180 | − | 2 | x | + | x | + | ( | 180 | − | 2 | ( | 180 | − | 2 | x | ) | ) | = | 180 |
| Left side of the equation = | 180 | − | 1 | x | + | ( | 180 | − | 2 | ( | 180 | − | 2 | x | ) | ) |
| 180 | − | 1 | x | + | ( | 180 | − | 2 | ( | 180 | − | 2 | x | ) | ) | = | 180 |
| Left side of the equation = | 180 | − | 1 | x | + | 180 | − | 2 | ( | 180 | − | 2 | x | ) |
| = | 360 | − | 1 | x | − | 2 | ( | 180 | − | 2 | x | ) |
| = | 360 | − | 1 | x | − | 2 | × | 180 | + | 2 | × | 2 | x |
| = | 360 | − | 1 | x | − | 360 | + | 4 | x |
| = | 0 | + | 3 | x |
| 0 | + | 3 | x | = | 180 |
| x | = | 180 | ÷ | 3 |
| = | 180 | × | 1 3 |
| = | 60 | × | 1 |
| x | = | 60 |