`|x – 2018| + |x – 2019| + |x – 2020| = 2` Tìm `x` nhé !!!!!

Question

`|x – 2018| + |x – 2019| + |x – 2020| = 2`
Tìm `x` nhé !!!!!

in progress 0
Kiệt Gia 1 year 2020-10-22T13:04:59+00:00 2 Answers 84 views 0

Answers ( )

    0
    2020-10-22T13:06:00+00:00

    $Dấu “=” xảy ra khi số đó là 2019$

    =>  

    {(x−2018)(2020−x)≥0x−2019=0 

    x – 2019 = 0

              x = 2019 +0 

              x = 2019

    $2018≤x≤2020$

    $x = 2019$
    $⇒x= 2019$

     

    0
    2020-10-22T13:06:54+00:00

    Đáp án:

    Ta có : 

    `|x – 2018| + |x – 2020|`

    `= |x – 2018| + |2020 – x| ≥ |x – 2018 + 2020 – x| = 2`

    `|x – 2019| ≥ 0`

    `=> |x – 2018| + |x – 2019| + |x – 2020| ≥ 2`

    Dấu “=” xây ra

    <=>  $\left \{ {{(x – 2018)(2020 – x) ≥ 0} \atop {x – 2019 = 0}} \right.$ 

    <=> $\left \{ {{2018 ≤ x ≤ 2020} \atop {x=2019}} \right.$ 

    `<=> x = 2019`

    Giải thích các bước giải:

     

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )