| 3 | − | 5 | ( | x | − | 3 | ) | = | 1 | − | 4 | ( | 2 | x | + | 1 | ) |
| Left side of the equation = | 3 | − | 5 | x | + | 5 | × | 3 |
| = | 3 | − | 5 | x | + | 15 |
| = | 18 | − | 5 | x |
| 18 | − | 5 | x | = | 1 | − | 4 | ( | 2 | x | + | 1 | ) |
| Right side of the equation = | 1 | − | 4 | × | 2 | x | − | 4 | × | 1 |
| = | 1 | − | 8 | x | − | 4 |
| = | - | 3 | − | 8 | x |
| 18 | − | 5 | x | = | - | 3 | − | 8 | x |
| - | 5 | x | + | 8 | x | = | - | 3 | − | 18 |
| 3 | x | = | - | 3 | − | 18 |
| 3 | x | = | - | 21 |
| x | = | - | 21 | ÷ | 3 |
| = | - | 21 | × | 1 3 |
| = | - | 7 | × | 1 |
| x | = | - | 7 |