| ( | x | − | 30 | ) | ( | 600 | − | ( | 10 | x | + | 1 | ) | ) | = | 10000 |
| Left side of the equation = | x | ( | 600 | − | ( | 10 | x | + | 1 | ) | ) | − | 30 | ( | 600 | − | ( | 10 | x | + | 1 | ) | ) |
| = | x | × | 600 | − | x | ( | 10 | x | + | 1 | ) | − | 30 | ( | 600 | − | ( | 10 | x | + | 1 | ) | ) |
| = | 600 | x | − | x | × | 10 | x | − | x | × | 1 | − | 30 | ( | 600 | − | ( | 10 | x | + | 1 | ) | ) |
| = | 599 | x | − | x | × | 10 | x | − | 30 | ( | 600 | − | ( | 10 | x | + | 1 | ) | ) |
| = | 599 | x | − | x | × | 10 | x | − | 30 | × | 600 | + | 30 | ( | 10 | x | + | 1 | ) |
| = | 599 | x | − | x | × | 10 | x | − | 18000 | + | 30 | ( | 10 | x | + | 1 | ) |
| = | 599 | x | − | x | × | 10 | x | − | 18000 | + | 30 | × | 10 | x | + | 30 | × | 1 |
| = | 599 | x | − | x | × | 10 | x | − | 18000 | + | 300 | x | + | 30 |
| = | 899 | x | − | x | × | 10 | x | − | 17970 |
| 899 | x | − | x | × | 10 | x | − | 17970 | = | 10000 |