| ( | x | × | 2 | + | 1 | ) | × | 2 | − | 5 | x | × | 2 | − | 5 | = | 0 |
| Left side of the equation = | ( | x | × | 2 | + | 1 | ) | × | 2 | − | 10 | x | − | 5 |
| ( | x | × | 2 | + | 1 | ) | × | 2 | − | 10 | x | − | 5 | = | 0 |
| Left side of the equation = | x | × | 2 | × | 2 | + | 1 | × | 2 | − | 10 | x | − | 5 |
| = | x | × | 4 | + | 2 | − | 10 | x | − | 5 |
| = | - | 6 | x | − | 3 |
| - | 6 | x | − | 3 | = | 0 |
| - | 6 | x | = | 0 | + | 3 |
| - | 6 | x | = | 3 |
| - | 3 | = | 6 | x |
| 6 | x | = | - | 3 |
| x | = | - | 3 | ÷ | 6 |
| = | - | 3 | × | 1 6 |
| = | - | 1 | × | 1 2 |
| x | = | - | 1 2 |
| x | = | - 0.5 |