| ( | x | − | 1999 | ) | ( | x | − | 2000 | ) | + | 2022 | = | 0 |
| Left side of the equation = | x | ( | x | − | 2000 | ) | − | 1999 | ( | x | − | 2000 | ) | + | 2022 |
| = | x | x | − | x | × | 2000 | − | 1999 | ( | x | − | 2000 | ) | + | 2022 |
| = | x | x | − | 2000 | x | − | 1999 | x | + | 1999 | × | 2000 | + | 2022 |
| = | x | x | − | 2000 | x | − | 1999 | x | + | 3998000 | + | 2022 |
| = | x | x | − | 3999 | x | + | 4000022 |
| x | x | − | 3999 | x | + | 4000022 | = | 0 |