| ( | 60 | − | 2 | x | ) | ( | 35 | − | x | ) | = | 1000 |
| Left side of the equation = | 60 | ( | 35 | − | x | ) | − | 2 | x | ( | 35 | − | x | ) |
| = | 60 | × | 35 | − | 60 | x | − | 2 | x | ( | 35 | − | x | ) |
| = | 2100 | − | 60 | x | − | 2 | x | ( | 35 | − | x | ) |
| = | 2100 | − | 60 | x | − | 2 | x | × | 35 | + | 2 | x | x |
| = | 2100 | − | 60 | x | − | 70 | x | + | 2 | x | x |
| = | 2100 | − | 130 | x | + | 2 | x | x |
| 2100 | − | 130 | x | + | 2 | x | x | = | 1000 |