| ( | 25 | + | x | ) | ( | 1000 | − | 20 | x | ) | = | 27000 |
| Left side of the equation = | 25 | ( | 1000 | − | 20 | x | ) | + | x | ( | 1000 | − | 20 | x | ) |
| = | 25 | × | 1000 | − | 25 | × | 20 | x | + | x | ( | 1000 | − | 20 | x | ) |
| = | 25000 | − | 500 | x | + | x | ( | 1000 | − | 20 | x | ) |
| = | 25000 | − | 500 | x | + | x | × | 1000 | − | x | × | 20 | x |
| = | 25000 | + | 500 | x | − | x | × | 20 | x |
| 25000 | + | 500 | x | − | x | × | 20 | x | = | 27000 |