| ( | x | − | 190 | ) | ( | 428 | − | 2 | x | ) | = | 0 |
| Left side of the equation = | x | ( | 428 | − | 2 | x | ) | − | 190 | ( | 428 | − | 2 | x | ) |
| = | x | × | 428 | − | x | × | 2 | x | − | 190 | ( | 428 | − | 2 | x | ) |
| = | 428 | x | − | x | × | 2 | x | − | 190 | × | 428 | + | 190 | × | 2 | x |
| = | 428 | x | − | x | × | 2 | x | − | 81320 | + | 380 | x |
| = | 808 | x | − | x | × | 2 | x | − | 81320 |
| 808 | x | − | x | × | 2 | x | − | 81320 | = | 0 |