| ( | 40 | − | 1 2 | x | ) | ( | 48 | + | 4 | x | ) | = | 512 |
| Left side of the equation = | 40 | ( | 48 | + | 4 | x | ) | − | 1 2 | x | ( | 48 | + | 4 | x | ) |
| = | 40 | × | 48 | + | 40 | × | 4 | x | − | 1 2 | x | ( | 48 | + | 4 | x | ) |
| = | 1920 | + | 160 | x | − | 1 2 | x | ( | 48 | + | 4 | x | ) |
| = | 1920 | + | 160 | x | − | 1 2 | x | × | 48 | − | 1 2 | x | × | 4 | x |
| = | 1920 | + | 160 | x | − | 24 | x | − | 2 | x | x |
| = | 1920 | + | 136 | x | − | 2 | x | x |
| 1920 | + | 136 | x | − | 2 | x | x | = | 512 |