| a | ( | 0 | + | 3 | ) | ( | 0 | − | 1 | ) | = | - | 3 |
| Left side of the equation = | a | × | 0 | ( | 0 | − | 1 | ) | + | a | × | 3 | ( | 0 | − | 1 | ) |
| = | a | × | 0 | × | 0 | − | a | × | 0 | × | 1 | + | a | × | 3 | ( | 0 | − | 1 | ) |
| = | a | × | 0 | − | a | × | 0 | + | a | × | 3 | ( | 0 | − | 1 | ) |
| = | 0 | a | + | a | × | 3 | ( | 0 | − | 1 | ) |
| = | 0 | a | + | a | × | 3 | × | 0 | − | a | × | 3 | × | 1 |
| = | 0 | a | + | a | × | 0 | − | a | × | 3 |
| = | - | 3 | a |
| - | 3 | a | = | - | 3 |
| 3 | = | 3 | a |
| 3 | a | = | 3 |
| a | = | 3 | ÷ | 3 |
| = | 3 | × | 1 3 |
| = | 1 | × | 1 |
| a | = | 1 |