Tìm x a)x3/7=34/14 b) x+30%x=1,3 c) x-25%x=1/2 d)|x-1/6|-6/16=25%

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1. Đáp án+Giải thích các bước giải:

   `b)`

   `x+30%x=1,3`

   `->x(1+30%)=1,3`

   `->1,3x=1,3`

   `->x=1`

   Vậy `x=1`

   `c)`

   `x-25%x=1/2`

   `->x(1-25%)=1/2`

   `->3/4x=1/2`

   `->x=1/2:3/4`

   `->x=2/3`

   Vậy `x=2/3`

   `d)`

   `|x-1/6|-6/16=25%`

   `->|x-1/6|=25%+6/16`

   `->|x-1/6|=5/8`

   `->` \(\left[ \begin{array}{l}x-\dfrac{1}{6}=\dfrac{5}{8}\\x-\dfrac{1}{6}=-\dfrac{5}{8}\end{array} \right.\) `->` \(\left[ \begin{array}{l}x=\dfrac{19}{24}\\x=-\dfrac{11}{24}\end{array} \right.\) 

   Vậy `x\in{19/24;-11/24}`

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2. `a)“x3/7=34/14`
      `x3/7=17/7`
      `x=17/7:3/7`
      `x=17/7. 7/3`
      `x=17/3`
   Vậy `x=17/3`

   `b)“ x+30%x=1,3`
       `x(1+3/10)=1,3`
       `x. 13/10=1,3`
       `x.1,3=1,3`
       `x=1,3:1,3`
       `x=1`
   Vậy `x=1`

   `c)“x-25%x=1/2` 

    `x(1-0,25)=0,5` 

    `x.0,75=0,5` 

    `x=0,5:0,75`   

   `x=2/3`

   Vậy `x=2/3`

   `d)“|x-1/6|-6/16=25%`
       `|x-1/6|-3/8=1/4`
       `|x-1/6|=1/4+3/8`
       `|x-1/6|=2/8+3/8`
       `|x-1/6|=5/8`
      `=>`\(\left[ \begin{array}{l}x-\frac{1}{6}=\frac{5}{8}\\x-\frac{1}{6}=\frac{-5}{8}\end{array} \right.\) `=>`\(\left[ \begin{array}{l}x=\frac{5}{8}+\frac{1}{6}  \\x=\frac{-5}{8}+\frac{1}{6}  \end{array} \right.\)`=>`\(\left[ \begin{array}{l}x=\frac{15}{24}+\frac{4}{24}  \\x=\frac{-15}{24} +\frac{4}{24} \end{array} \right.\)`

   =>`\(\left[ \begin{array}{l}x=\frac{19}{24} \\x=\frac{-11}{24} \end{array} \right.\) 
   Vậy \(\left[ \begin{array}{l}x=\frac{19}{24} \\x=\frac{-11}{24} \end{array} \right.\) 

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