| ( | 30 | − | 1 | ÷ | 10 | × | x | ) | ( | x | − | 20 | ) | = | 0 |
| Left side of the equation = | 30 | ( | x | − | 20 | ) | − | 1 | ÷ | 10 | × | x | ( | x | − | 20 | ) |
| = | 30 | ( | x | − | 20 | ) | − | 1 10 | x | ( | x | − | 20 | ) |
| = | 30 | x | − | 30 | × | 20 | − | 1 10 | x | ( | x | − | 20 | ) |
| = | 30 | x | − | 600 | − | 1 10 | x | ( | x | − | 20 | ) |
| = | 30 | x | − | 600 | − | 1 10 | x | x | + | 1 10 | x | × | 20 |
| = | 30 | x | − | 600 | − | 1 10 | x | x | + | 2 | x |
| = | 32 | x | − | 600 | − | 1 10 | x | x |
| 32 | x | − | 600 | − | 1 10 | x | x | = | 0 |