| ( | x | + | 6 | ) | ( | x | − | 4 | ) | ( | x | + | 1 | ) | ( | x | − | 15 | ) | = | 0 |
| Left side of the equation = | x | ( | x | − | 4 | ) | ( | x | + | 1 | ) | ( | x | − | 15 | ) | + | 6 | ( | x | − | 4 | ) | ( | x | + | 1 | ) | ( | x | − | 15 | ) |
| = | x | x | ( | x | + | 1 | ) | ( | x | − | 15 | ) | − | x | × | 4 | ( | x | + | 1 | ) | ( | x | − | 15 | ) | + | 6 | ( | x | − | 4 | ) | ( | x | + | 1 | ) | ( | x | − | 15 | ) |
| = | x | x | x | ( | x | − | 15 | ) | + | x | x | × | 1 | ( | x | − | 15 | ) | − | x | × | 4 | ( | x | + | 1 | ) | ( | x | − | 15 | ) |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | ( | x | − | 15 | ) |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |
| = | x | x | x | x | − | x | x | x | × | 15 | + | x | x | × | 1 | x |