| 2 | ( | 2 | × | 4 | − | 1 | ) | + | 1 | = | 3 | ( | 4 | + | a | ) |
| Left side of the equation = | 2 | × | 2 | × | 4 | − | 2 | × | 1 | + | 1 |
| = | 16 | − | 2 | + | 1 |
| = | 15 |
| 15 | = | 3 | ( | 4 | + | a | ) |
| Right side of the equation = | 3 | × | 4 | + | 3 | a |
| = | 12 | + | 3 | a |
| 15 | = | 12 | + | 3 | a |
| - | 3 | a | = | 12 | − | 15 |
| - | 3 | a | = | - | 3 |
| 3 | = | 3 | a |
| 3 | a | = | 3 |
| a | = | 3 | ÷ | 3 |
| = | 3 | × | 1 3 |
| = | 1 | × | 1 |
| a | = | 1 |