| ( | 52 | − | 40 | + | x | ) | ( | 180 | − | 10 | x | ) | = | 2000 |
| Left side of the equation = | 52 | ( | 180 | − | 10 | x | ) | − | 40 | ( | 180 | − | 10 | x | ) | + | x | ( | 180 | − | 10 | x | ) |
| = | 52 | × | 180 | − | 52 | × | 10 | x | − | 40 | ( | 180 | − | 10 | x | ) | + | x | ( | 180 | − | 10 | x | ) |
| = | 9360 | − | 520 | x | − | 40 | ( | 180 | − | 10 | x | ) | + | x | ( | 180 | − | 10 | x | ) |
| = | 9360 | − | 520 | x | − | 40 | × | 180 | + | 40 | × | 10 | x | + | x | ( | 180 | − | 10 | x | ) |
| = | 9360 | − | 520 | x | − | 7200 | + | 400 | 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 |