| X | ( | - | 2 | X | + | 180 | ) | = | 600 | + | 50 | ( | - | 2 | X | + | 180 | ) |
| Left side of the equation = | - | X | × | 2 | X | + | X | × | 180 |
| - | X | × | 2 | X | + | 180 | X | = | 600 | + | 50 | ( | - | 2 | X | + | 180 | ) |
| Right side of the equation = | 600 | − | 50 | × | 2 | X | + | 50 | × | 180 |
| = | 600 | − | 100 | X | + | 9000 |
| = | 9600 | − | 100 | X |
| - | X | × | 2 | X | + | 180 | X | = | 9600 | − | 100 | X |