| ( | 12 | + | X | ) | ( | 180 | − | 10 | X | ) | = | 2000 |
| Left side of the equation = | 12 | ( | 180 | − | 10 | X | ) | + | X | ( | 180 | − | 10 | X | ) |
| = | 12 | × | 180 | − | 12 | × | 10 | X | + | X | ( | 180 | − | 10 | X | ) |
| = | 2160 | − | 120 | X | + | X | ( | 180 | − | 10 | X | ) |
| = | 2160 | − | 120 | X | + | X | × | 180 | − | X | × | 10 | X |
| = | 2160 | + | 60 | X | − | X | × | 10 | X |
| 2160 | + | 60 | X | − | X | × | 10 | X | = | 2000 |