| 6 | ( | 6 | X | − | 50 | ) | = | 7 | ( | 5 | X | − | 50 | ) |
| Left side of the equation = | 6 | × | 6 | X | − | 6 | × | 50 |
| = | 36 | X | − | 300 |
| 36 | X | − | 300 | = | 7 | ( | 5 | X | − | 50 | ) |
| Right side of the equation = | 7 | × | 5 | X | − | 7 | × | 50 |
| = | 35 | X | − | 350 |
| 36 | X | − | 300 | = | 35 | X | − | 350 |
| 36 | X | − | 35 | X | = | - | 350 | + | 300 |
| X | = | - | 350 | + | 300 |
| X | = | - | 350 | + | 300 |
| X | = | - | 50 |