Đề là vậy phải không : | 2017 - x | + | 2018 - x | + | 2019 - x | = 2
Nếu x ≤ 2017 thì | 2017 - x | = 2017 - x
| 2018 - x | = 2018 - x
| 2019 - x | = 2019 - x
Pt (=) 2017-x+2018-x+2019-x = 2
(=) -3x + 6054 = 2
(=) 3x = 6052
(=) x = 6052/3 ( loại, vì > 2017 )
Nếu 2017 < x < 2018 thì | 2017 - x | = x - 2017 ; | 2018 - x | = 2018 - x ; | 2019 - x | = 2019 - x
Pt (=) x-2017+2018-x+2019-x = 2
(=) x = -2018 ( loại )
Nếu 2018 ≤ x ≤ 2019 thì | 2017-x| = x-2017 ; | 2018-x| = x-2018 ; | 2019-x | = 2019-x
Pt (=) x-2017+x-2018+2019-x = 2
(=) x = 2018 ( TM )
Nếu x > 2019 thì | 2017-x | = x-2017 ; | 2018-x | = x-2018 ; | 2019-x | = x-2019
Pt(=) x-2017+x-2018+x-2019 = 2
(=) 3x = 6056
(=) x = 6056/3 ( loại )
