| ( | 1 | + | x | ) | ( | 1000 | − | 50 | x | ) | = | 10000 |
| Left side of the equation = | 1 | ( | 1000 | − | 50 | x | ) | + | x | ( | 1000 | − | 50 | x | ) |
| = | 1 | × | 1000 | − | 1 | × | 50 | x | + | x | ( | 1000 | − | 50 | x | ) |
| = | 1000 | − | 50 | x | + | x | ( | 1000 | − | 50 | x | ) |
| = | 1000 | − | 50 | x | + | x | × | 1000 | − | x | × | 50 | x |
| = | 1000 | + | 950 | x | − | x | × | 50 | x |
| 1000 | + | 950 | x | − | x | × | 50 | x | = | 10000 |