| 3000 | + | ( | 100 | − | x | ) | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) | − | 6000 | = | 15200 |
| Left side of the equation = | - | 3000 | + | ( | 100 | − | x | ) | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) |
| - | 3000 | + | ( | 100 | − | x | ) | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) | = | 15200 |
| Left side of the equation = | - | 3000 | + | 100 | ( | 300 | − | 2 | x | ) | − | x | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) |
| = | - | 3000 | + | 100 | × | 300 | − | 100 | × | 2 | x | − | x | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) |
| = | - | 3000 | + | 30000 | − | 200 | x | − | x | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) |
| = | 27000 | − | 200 | x | − | x | ( | 300 | − | 2 | x | ) | + | 50 | ( | 400 | − | 2 | x | ) |
| = | 27000 | − | 200 | x | − | x | × | 300 | + | x | × | 2 | x | + | 50 | ( | 400 | − | 2 | x | ) |
| = | 27000 | − | 500 | x | + | x | × | 2 | x | + | 50 | ( | 400 | − | 2 | x | ) |
| = | 27000 | − | 500 | x | + | x | × | 2 | x | + | 50 | × | 400 | − | 50 | × | 2 | x |
| = | 27000 | − | 500 | x | + | x | × | 2 | x | + | 20000 | − | 100 | x |
| = | 47000 | − | 600 | x | + | x | × | 2 | x |
| 47000 | − | 600 | x | + | x | × | 2 | x | = | 15200 |