| ( | x | − | 22 | ) | ( | 312 | − | 4 | x | ) | = | 3640 |
| Left side of the equation = | x | ( | 312 | − | 4 | x | ) | − | 22 | ( | 312 | − | 4 | x | ) |
| = | x | × | 312 | − | x | × | 4 | x | − | 22 | ( | 312 | − | 4 | x | ) |
| = | 312 | x | − | x | × | 4 | x | − | 22 | × | 312 | + | 22 | × | 4 | x |
| = | 312 | x | − | x | × | 4 | x | − | 6864 | + | 88 | x |
| = | 400 | x | − | x | × | 4 | x | − | 6864 |
| 400 | x | − | x | × | 4 | x | − | 6864 | = | 3640 |