| 20 | − | 10 | x | − | ( | 9 | + | x | ) | ( | 24 | + | 9 | x | ) | = | 0 |
| Left side of the equation = | 20 | − | 10 | x | − | 9 | ( | 24 | + | 9 | x | ) | − | x | ( | 24 | + | 9 | x | ) |
| = | 20 | − | 10 | x | − | 9 | × | 24 | − | 9 | × | 9 | x | − | x | ( | 24 | + | 9 | x | ) |
| = | 20 | − | 10 | x | − | 216 | − | 81 | x | − | x | ( | 24 | + | 9 | x | ) |
| = | - | 196 | − | 91 | x | − | x | ( | 24 | + | 9 | x | ) |
| = | - | 196 | − | 91 | x | − | x | × | 24 | − | x | × | 9 | x |
| = | - | 196 | − | 115 | x | − | x | × | 9 | x |
| - | 196 | − | 115 | x | − | x | × | 9 | x | = | 0 |