| x | − | ( | ( | 1 4 | x | + | 30 | ) | + | ( | 1 5 | x | − | 15 | ) | + | 1 2 | x | ) | = | 0 |
| Left side of the equation = | x | − | ( | 1 4 | x | + | 30 | ) | − | ( | 1 5 | x | − | 15 | ) | − | 1 2 | x |
| = | 1 2 | x | − | ( | 1 4 | x | + | 30 | ) | − | ( | 1 5 | x | − | 15 | ) |
| = | 1 2 | x | − | 1 4 | x | − | 30 | − | ( | 1 5 | x | − | 15 | ) |
| = | 1 4 | x | − | 30 | − | ( | 1 5 | x | − | 15 | ) |
| = | 1 4 | x | − | 30 | − | 1 5 | x | + | 15 |
| = | 1 20 | x | − | 15 |
1 20 | x | − | 15 | = | 0 |
1 20 | x | = | 0 | + | 15 |
1 20 | x | = | 15 |
| x | = | 15 | ÷ | 1 20 |
| = | 15 | × | 20 |
| x | = | 300 |