| ( | 4 | − | x | ) | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 180 | − | 28 | ( | 4 | − | x | ) | − | 5 | x | + | 25 | = | 0 |
| Left side of the equation = | ( | 4 | − | x | ) | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 | ( | 4 | − | x | ) | − | 5 | x |
| ( | 4 | − | x | ) | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 | ( | 4 | − | x | ) | − | 5 | x | = | 0 |
| Left side of the equation = | 4 | ( | 4 | + | x | ) | ( | x | − | 5 | ) | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 | ( | 4 | − | x | ) | − | 5 | x |
| = | 4 | × | 4 | ( | x | − | 5 | ) | + | 4 | x | ( | x | − | 5 | ) | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 | ( | 4 | − | x | ) |
| = | 16 | ( | x | − | 5 | ) | + | 4 | x | ( | x | − | 5 | ) | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 | ( | 4 | − | x | ) | − | 5 |
| = | 16 | x | − | 16 | × | 5 | + | 4 | x | ( | x | − | 5 | ) | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 |
| = | 16 | x | − | 80 | + | 4 | x | ( | x | − | 5 | ) | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | + | 205 | − | 28 | ( | 4 | − | x | ) |
| = | 11 | x | + | 125 | + | 4 | x | ( | x | − | 5 | ) | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | − | 28 | ( | 4 | − | x | ) |
| = | 11 | x | + | 125 | + | 4 | x | x | − | 4 | x | × | 5 | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) |
| = | 11 | x | + | 125 | + | 4 | x | x | − | 20 | x | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | − | 28 |
| = | - | 9 | x | + | 125 | + | 4 | x | x | − | x | ( | 4 | + | x | ) | ( | x | − | 5 | ) | − | 28 | ( | 4 | − | x | ) |
| = | - | 9 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | ( | x | − | 5 | ) | − | x | x | ( | x | − | 5 | ) |
| = | - | 9 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | x | + | x | × | 4 | × | 5 |
| = | - | 9 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | x | + | x | × | 20 | − | x |
| = | 11 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | x | − | x | x | ( | x | − | 5 | ) |
| = | 11 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | x | − | x | x | x |
| = | 11 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | x | − | x | x | x |
| = | 11 | x | + | 125 | + | 4 | x | x | − | x | × | 4 | x | − | x | x | x |
| = | 39 | x | + | 13 | + | 4 | x | x | − | x | × | 4 | x | − | x | x | x |
| 39 | x | + | 13 | + | 4 | x | x | − | x | × | 4 | x | − | x | x | x | = | 0 |