| ( | 200 | + | 5 | x | ) | ( | 36 | − | x | ) | = | 6900 |
| Left side of the equation = | 200 | ( | 36 | − | x | ) | + | 5 | x | ( | 36 | − | x | ) |
| = | 200 | × | 36 | − | 200 | x | + | 5 | x | ( | 36 | − | x | ) |
| = | 7200 | − | 200 | x | + | 5 | x | ( | 36 | − | x | ) |
| = | 7200 | − | 200 | x | + | 5 | x | × | 36 | − | 5 | x | x |
| = | 7200 | − | 200 | x | + | 180 | x | − | 5 | x | x |
| = | 7200 | − | 20 | x | − | 5 | x | x |
| 7200 | − | 20 | x | − | 5 | x | x | = | 6900 |