| ( | 3 | − | x | ) | ( | 5 | − | x | ) | ( | 1 | − | x | ) | = | 12 | ( | 5 | − | x | ) | − | 24 |
| Left side of the equation = | 3 | ( | 5 | − | x | ) | ( | 1 | − | x | ) | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 3 | × | 5 | ( | 1 | − | x | ) | − | 3 | x | ( | 1 | − | x | ) | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | ( | 1 | − | x | ) | − | 3 | x | ( | 1 | − | x | ) | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | × | 1 | − | 15 | x | − | 3 | x | ( | 1 | − | x | ) | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | − | 15 | x | − | 3 | x | ( | 1 | − | x | ) | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | − | 15 | x | − | 3 | x | × | 1 | + | 3 | x | x | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | − | 15 | x | − | 3 | x | + | 3 | x | x | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | − | 18 | x | + | 3 | x | x | − | x | ( | 5 | − | x | ) | ( | 1 | − | x | ) |
| = | 15 | − | 18 | x | + | 3 | x | x | − | x | × | 5 | ( | 1 | − | x | ) | + | x | x | ( | 1 | − | x | ) |
| = | 15 | − | 18 | x | + | 3 | x | x | − | x | × | 5 | × | 1 | + | x | × | 5 | x |
| = | 15 | − | 18 | x | + | 3 | x | x | − | x | × | 5 | + | x | × | 5 | x | + | x |
| = | 15 | − | 23 | x | + | 3 | x | x | + | x | × | 5 | x | + | x | x | ( | 1 | − | x | ) |
| = | 15 | − | 23 | x | + | 3 | x | x | + | x | × | 5 | x | + | x | x | × | 1 |
| 15 | − | 23 | x | + | 3 | x | x | + | x | × | 5 | x | + | x | x | × | 1 | = | 12 | ( | 5 | − | x | ) | − | 24 |
| Right side of the equation = | 12 | × | 5 | − | 12 | x | − | 24 |
| = | 60 | − | 12 | x | − | 24 |
| = | 36 | − | 12 | x |
| 15 | − | 23 | x | + | 3 | x | x | + | x | × | 5 | x | + | x | x | × | 1 | = | 36 | − | 12 | x |