Tìm x∈Q, biết: ∣2,5−x∣=1,3 Tìm x∈Q, biết: ∣x−0,2∣=1,6

Question

Tìm x∈Q, biết: ∣2,5−x∣=1,3
Tìm x∈Q, biết: ∣x−0,2∣=1,6

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Doris 6 years 2020-11-07T01:57:40+00:00 2 Answers 74 views 0

Answers ( )

  1. mit
    0
    2020-11-07T01:59:07+00:00
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    a) $|2,5-x|=1,3$

    TH1: $2,5-x=1,3$

    $↔x=2,5-1,3$

    $↔x=1,2$

    TH2: $2,5-x=-1,3$

    $↔x=2,5-(-1,3)$

    $↔x=3,8$

    b) $|x-0,2|=1,6$

    TH1: $x-0,2=1,6$

    $↔x=1,6+0,2$

    $↔x=1,8$

    TH2: $x-0,2=-1,6$

    $↔x=-1,6+0,2$

    $↔x=-1,4$

     

  2. Farah
    0
    2020-11-07T01:59:17+00:00
    Reply

    Đáp án:

    `x∈{1,2;-3,8}`

    `x∈{1,8;-1,4}`

    Giải thích các bước giải:

    `|2,5-x|=1,3`

    `<=>`\(\left[ \begin{array}{l}2,5-x=1,3\\2,5-x=-1,3\end{array} \right.\)

    `<=>`\(\left[ \begin{array}{l}x=1,2\\x=-3.8\end{array} \right.\)

    Vậy: `x∈{1,2;-3,8}`

    `|x-0,2|=1,6`

    `<=>`\(\left[ \begin{array}{l}x-0,2=1,6\\x-0,2=-1,6\end{array} \right.\) 

    `<=>`\(\left[ \begin{array}{l}x=1,8\\x=-1,4\end{array} \right.\) 

    Vậy: `x∈{1,8;-1,4}`

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