| ( | 5000 | − | 10 | x | ) | ( | 2 | + | 1 2 | x | ) | − | 400 | x | − | 2 | × | 5000 | = | 39600 |
| Left side of the equation = | ( | 5000 | − | 10 | x | ) | ( | 2 | + | 1 2 | x | ) | − | 400 | x | − | 10000 |
| ( | 5000 | − | 10 | x | ) | ( | 2 | + | 1 2 | x | ) | − | 400 | x | − | 10000 | = | 39600 |
| Left side of the equation = | 5000 | ( | 2 | + | 1 2 | x | ) | − | 10 | x | ( | 2 | + | 1 2 | x | ) | − | 400 | x | − | 10000 |
| = | 5000 | × | 2 | + | 5000 | × | 1 2 | x | − | 10 | x | ( | 2 | + | 1 2 | x | ) | − | 400 | x | − | 10000 |
| = | 10000 | + | 2500 | x | − | 10 | x | ( | 2 | + | 1 2 | x | ) | − | 400 | x | − | 10000 |
| = | 0 | + | 2100 | x | − | 10 | x | ( | 2 | + | 1 2 | x | ) |
| = | 0 | + | 2100 | x | − | 10 | x | × | 2 | − | 10 | x | × | 1 2 | x |
| = | 0 | + | 2100 | x | − | 20 | x | − | 5 | x | x |
| = | 0 | + | 2080 | x | − | 5 | x | x |
| 0 | + | 2080 | x | − | 5 | x | x | = | 39600 |