| 16 | ( | 3 4 | a | − | 300 | ) | = | 13 | ( | a | − | 405 | ) |
| Left side of the equation = | 16 | × | 3 4 | a | − | 16 | × | 300 |
| = | 12 | a | − | 4800 |
| 12 | a | − | 4800 | = | 13 | ( | a | − | 405 | ) |
| Right side of the equation = | 13 | a | − | 13 | × | 405 |
| = | 13 | a | − | 5265 |
| 12 | a | − | 4800 | = | 13 | a | − | 5265 |
| 12 | a | − | 13 | a | = | - | 5265 | + | 4800 |
| - | a | = | - | 5265 | + | 4800 |
| - | a | = | - | 5265 | + | 4800 |
| - | a | = | - | 465 |
| 465 | = | a |
| a | = | 465 |