| 2 | x | x | + | ( | 9 | − | 2 | x | ) | ( | 9 | − | 2 | x | ) | − | 100 | = | 0 |
| Left side of the equation = | 2 | x | x | + | 9 | ( | 9 | − | 2 | x | ) | − | 2 | x | ( | 9 | − | 2 | x | ) | − | 100 |
| = | 2 | x | x | + | 9 | × | 9 | − | 9 | × | 2 | x | − | 2 | x | ( | 9 | − | 2 | x | ) | − | 100 |
| = | 2 | x | x | + | 81 | − | 18 | x | − | 2 | x | ( | 9 | − | 2 | x | ) | − | 100 |
| = | 2 | x | x | − | 19 | − | 18 | x | − | 2 | x | ( | 9 | − | 2 | x | ) |
| = | 2 | x | x | − | 19 | − | 18 | x | − | 2 | x | × | 9 | + | 2 | x | × | 2 |
| = | 2 | x | x | − | 19 | − | 18 | x | − | 18 | x | + | 4 | x | x |
| = | 2 | x | x | − | 19 | − | 36 | x | + | 4 | x | x |
| 2 | x | x | − | 19 | − | 36 | x | + | 4 | x | x | = | 0 |