Tìm x: /x/+2x- $\frac{1}{2}$ = $\frac{-3}{2}$

Question

Tìm x:
/x/+2x- $\frac{1}{2}$ = $\frac{-3}{2}$

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Ben Gia 6 years 2020-11-28T02:32:41+00:00 2 Answers 57 views 0

Answers ( )

  1. Giakhanh
    0
    2020-11-28T02:34:35+00:00
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    $|x|+2x=\dfrac{1}{2}-\dfrac{3}{2}$

    $\Leftrightarrow |x|+2x=-1$      (*)

    – TH1: $x\ge 0$

    (*) $\Leftrightarrow x+2x=-1$

    $\Leftrightarrow x=\dfrac{-1}{3}<0$ (loại)

    – TH2: $x<0$

    (*) $\Leftrightarrow 2x-x=-1$

    $\Leftrightarrow x=-1$ (TM)

    Vậy $S=\{-1\}$

  2. Calantha
    0
    2020-11-28T02:34:36+00:00
    Reply

    Đáp án:

     

    Giải thích các bước giải:

    `|x|+2x-1/2=-3/2`
    `=>|x|=-3/2+1/2-2x`
    `=>|x|=-2x-1`
    `ĐK:-2x-1>=0`
    `=>2x<=-1`
    `=>x<=-1/2`
    `=>`\(\left[ \begin{array}{l}x=-2x-1\\x=2x+1\end{array} \right.\) 
    `=>`\(\left[ \begin{array}{l}x+2x=-1\\x-2x=1\end{array} \right.\) 
    `=>`\(\left[ \begin{array}{l}x= \dfrac{-1}{3}(Loại)\\x=-1(tm)\end{array} \right.\)
    Vậy `x=-1`

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