| ( | x | − | 6 | ) | ( | 160 | − | 10 | x | ) | = | 225 |
| Left side of the equation = | x | ( | 160 | − | 10 | x | ) | − | 6 | ( | 160 | − | 10 | x | ) |
| = | x | × | 160 | − | x | × | 10 | x | − | 6 | ( | 160 | − | 10 | x | ) |
| = | 160 | x | − | x | × | 10 | x | − | 6 | × | 160 | + | 6 | × | 10 | x |
| = | 160 | x | − | x | × | 10 | x | − | 960 | + | 60 | x |
| = | 220 | x | − | x | × | 10 | x | − | 960 |
| 220 | x | − | x | × | 10 | x | − | 960 | = | 225 |