| 800 | + | ( | 4 | − | x | ) | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) | − | 2 | = | 1250 |
| Left side of the equation = | 798 | + | ( | 4 | − | x | ) | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) |
| 798 | + | ( | 4 | − | x | ) | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) | = | 1250 |
| Left side of the equation = | 798 | + | 4 | ( | 200 | + | 500 | − | 50 | x | ) | − | x | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) |
| = | 798 | + | 4 | × | 200 | + | 4 | × | 500 | − | 4 | × | 50 | x | − | x | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) |
| = | 798 | + | 800 | + | 2000 | − | 200 | x | − | x | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) |
| = | 3598 | − | 200 | x | − | x | ( | 200 | + | 500 | − | 50 | x | ) | + | ( | 50 | x | − | 100 | ) |
| = | 3598 | − | 200 | x | − | x | × | 200 | − | x | × | 500 | + | x | × | 50 | x | + | ( | 50 | x | − | 100 | ) |
| = | 3598 | − | 900 | x | + | x | × | 50 | x | + | ( | 50 | x | − | 100 | ) |
| = | 3598 | − | 900 | x | + | x | × | 50 | x | + | 50 | x | − | 100 |
| = | 3498 | − | 850 | x | + | x | × | 50 | x |
| 3498 | − | 850 | x | + | x | × | 50 | x | = | 1250 |