| - | 2 | x | + | 3 | ( | 9 | − | x | ) | = | 148 | − | 117 |
| Left side of the equation = | - | 2 | x | + | 3 | × | 9 | − | 3 | x |
| = | - | 2 | x | + | 27 | − | 3 | x |
| = | - | 5 | x | + | 27 |
| - | 5 | x | + | 27 | = | 148 | − | 117 |
| Right side of the equation = | 31 |
| - | 5 | x | + | 27 | = | 31 |
| - | 5 | x | = | 31 | − | 27 |
| - | 5 | x | = | 4 |
| - | 4 | = | 5 | x |
| 5 | x | = | - | 4 |
| x | = | - | 4 | ÷ | 5 |
| = | - | 4 | × | 1 5 |
| x | = | - | 4 5 |
| x | = | - 0.8 |