| ( | 100 | − | 5 | ) | × | 8 | − | x | − | 20 | × | 8 | = | 200 |
| Left side of the equation = | ( | 100 | − | 5 | ) | × | 8 | − | x | − | 160 |
| ( | 100 | − | 5 | ) | × | 8 | − | x | − | 160 | = | 200 |
| Left side of the equation = | 100 | × | 8 | − | 5 | × | 8 | − | x | − | 160 |
| = | 800 | − | 40 | − | x | − | 160 |
| = | 600 | − | x |
| 600 | − | x | = | 200 |
| - | x | = | 200 | − | 600 |
| - | x | = | - | 400 |
| 400 | = | x |
| x | = | 400 |