| ( | x | − | 3 | ) | ( | 500 | − | 10 | × | 10 | ) | = | 800 |
| Left side of the equation = | x | ( | 500 | − | 10 | × | 10 | ) | − | 3 | ( | 500 | − | 10 | × | 10 | ) |
| = | x | × | 500 | − | x | × | 10 | × | 10 | − | 3 | ( | 500 | − | 10 | × | 10 | ) |
| = | x | × | 500 | − | x | × | 100 | − | 3 | ( | 500 | − | 10 | × | 10 | ) |
| = | 400 | x | − | 3 | ( | 500 | − | 10 | × | 10 | ) |
| = | 400 | x | − | 3 | × | 500 | + | 3 | × | 10 | × | 10 |
| = | 400 | x | − | 1500 | + | 300 |
| = | 400 | x | − | 1200 |
| 400 | x | − | 1200 | = | 800 |
| 400 | x | = | 800 | + | 1200 |
| 400 | x | = | 2000 |
| x | = | 2000 | ÷ | 400 |
| = | 2000 | × | 1 400 |
| = | 5 | × | 1 |
| x | = | 5 |