| ( | 1000 | − | 100 | x | ) | ( | 30 | + | x | ) | − | ( | 1000 | − | 100 | x | ) | × | 20 | x | = | 9600 |
| Left side of the equation = | 1000 | ( | 30 | + | x | ) | − | 100 | x | ( | 30 | + | x | ) | − | ( | 1000 | − | 100 | x | ) | × | 20 | x |
| = | 1000 | × | 30 | + | 1000 | x | − | 100 | x | ( | 30 | + | x | ) | − | ( | 1000 | − | 100 | x | ) | × | 20 | x |
| = | 30000 | + | 1000 | x | − | 100 | x | ( | 30 | + | x | ) | − | ( | 1000 | − | 100 | x | ) | × | 20 | x |
| = | 30000 | + | 1000 | x | − | 100 | x | × | 30 | − | 100 | x | x | − | ( | 1000 | − | 100 | x | ) | × | 20 | x |
| = | 30000 | + | 1000 | x | − | 3000 | x | − | 100 | x | x | − | ( | 1000 | − | 100 | x | ) | × | 20 | x |
| = | 30000 | − | 2000 | x | − | 100 | x | x | − | ( | 1000 | − | 100 | x | ) | × | 20 | x |
| = | 30000 | − | 2000 | x | − | 100 | x | x | − | 1000 | × | 20 | x | + | 100 | x | × | 20 |
| = | 30000 | − | 2000 | x | − | 100 | x | x | − | 20000 | x | + | 2000 | x | x |
| = | 30000 | − | 22000 | x | − | 100 | x | x | + | 2000 | x | x |
| 30000 | − | 22000 | x | − | 100 | x | x | + | 2000 | x | x | = | 9600 |