| ( | 84 | − | 2 | x | ) | ( | x | − | 28 | ) | = | 96 |
| Left side of the equation = | 84 | ( | x | − | 28 | ) | − | 2 | x | ( | x | − | 28 | ) |
| = | 84 | x | − | 84 | × | 28 | − | 2 | x | ( | x | − | 28 | ) |
| = | 84 | x | − | 2352 | − | 2 | x | ( | x | − | 28 | ) |
| = | 84 | x | − | 2352 | − | 2 | x | x | + | 2 | x | × | 28 |
| = | 84 | x | − | 2352 | − | 2 | x | x | + | 56 | x |
| = | 140 | x | − | 2352 | − | 2 | x | x |
| 140 | x | − | 2352 | − | 2 | x | x | = | 96 |