| - | 3 | ( | x | + | 3 | ) | × | 24 | = | 0 |
| Left side of the equation = | - | 72 | ( | x | + | 3 | ) |
| - | 72 | ( | x | + | 3 | ) | = | 0 |
| Left side of the equation = | - | 72 | x | − | 72 | × | 3 |
| = | - | 72 | x | − | 216 |
| - | 72 | x | − | 216 | = | 0 |
| - | 72 | x | = | 0 | + | 216 |
| - | 72 | x | = | 216 |
| - | 216 | = | 72 | x |
| 72 | x | = | - | 216 |
| x | = | - | 216 | ÷ | 72 |
| = | - | 216 | × | 1 72 |
| = | - | 3 | × | 1 |
| x | = | - | 3 |