1,2/3+1/3.x=1/2.x-1 2,|5/18|-X-1/4=3/8 3,2.|1/3-X|+1/3=4 4,x/3=2

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1. $#Dino$

   `a) 2/3+1/3x=1/2x-1`

   `⇒1/3x-1/2x=-2/3-1`

   `⇒-1/6x=-5/3`

   `⇒x=10`

   Vậy `x=10`

   `b) |5/18|-x-1/4=3/8`

   `⇒-x=-5/18+3/8+1/4`

   `⇒-x=-25/72`

   `⇒x=-25/72`

   `c) 2.|1/3-x|+1/3=4`

   `⇒|1/3-x|=(4-1/3):2=11/6`

   `1) 1/3-x=11/6⇒x=1/3-11/6=-3/2`

   `2) 1/3-x=-11/6⇒x=1/3+11/6=13/6`

   Vậy…..

   `d) x/3=2`

   `⇒x=(3xx2)/1=6`

   Vậy

    

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2. Đáp án:

    1. $\dfrac{2}{3} + \dfrac{1}{3}x = \dfrac{1}{2}x – 1$ 

      $\dfrac{1}{3}x – \dfrac{1}{2}x = – 1 – \dfrac{2}{3}$ 

      $- \dfrac{1}{6}x = – \dfrac{5}{3}$ 

      $x = – \dfrac{5}{3} : (- \dfrac{1}{6})$ 

       $x = 10$ 

   2. $|\dfrac{5}{18}| – x – \dfrac{1}{4} = \dfrac{3}{8}$ 

      $\dfrac{5}{18} – x – \dfrac{1}{4} = \dfrac{3}{8}$ 

      $- x = \dfrac{3}{8} – \dfrac{5}{18} + \dfrac{1}{4}$ 

      $- x = \dfrac{25}{72}$ 

      $x = – \dfrac{25}{72}$  

   3. $\dfrac{3}{2}|\dfrac{1}{3} – x| + \dfrac{1}{3} = 4$ 

    $\dfrac{3}{2}|\dfrac{1}{3} – x| = 4 – \dfrac{1}{3}$ 

     $\dfrac{3}{2}|\dfrac{1}{3} – x| = \dfrac{11}{3}$ 

     $|\dfrac{1}{3} – x| = \dfrac{11}{3} : \dfrac{1}{3}$ 

     $|\dfrac{1}{3} – x| = 11$ 

   Suy ra: 

   *) $\dfrac{1}{3} – x = 11 \to x = \dfrac{1}{3} – 11$ 

        $x = – \dfrac{32}{3}$ 

   *) $\dfrac{1}{3} – x = – 11 \to x = 11 + \dfrac{1}{3}$ 

         $x = \dfrac{34}{3}$ 

   4. $\dfrac{x}{3} = 2$ 

       $x.\dfrac{1}{3} = 2$ 

       $x = 2 : \dfrac{1}{3}$ 

        $x = 6$

   Giải thích các bước giải:

    

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