|3x-2|=5 3\4+1\4:x=-2 {2\3} ²:{-8} – {-1\4+9\20}:9\5

Question

|3x-2|=5
3\4+1\4:x=-2
{2\3} ²:{-8} – {-1\4+9\20}:9\5

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Audrey 10 phút 2021-09-09T14:12:59+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-09-09T14:14:01+00:00

    `| 3x – 2 | = 5`

    `⇔` \(\left[ \begin{array}{l}3x – 2 = 5\\3x – 2 = -5\end{array} \right.\) 

    `⇔` \(\left[ \begin{array}{l}3x = 7\\3x = – 3\end{array} \right.\) 

    `⇔` \(\left[ \begin{array}{l}x = 7/3\\x = – 1\end{array} \right.\) 

    Vậy , `x ∈ { 7/3 ; – 1 }`

    ____________________________________________

    `3/4 + 1/4 : x = – 2`

    `⇔ 1/4 : x      = – 2 – 3/4` 

    `⇔ 1/4 : x      = -11/4`  

    `⇔         x      = -11/4 : 1/4`  

    `⇔          x      = -11`   

    Vậy , `x = -11`

    _____________________________________________

    `( 2/3 )^2 : ( – 8 ) – ( – 1/4 + 9/20 ) : 9/5`

    `= 4/9 : ( – 8 ) – 1/5 : 9/5`

    `= -1/18 – 1/9`

    `= -1/6`

    0
    2021-09-09T14:14:40+00:00

    Đáp án:

    ở dưới

    nếu thấy hay thì cho mình xin

    – 5 sao

    – cám ơn

    – hay nhất

    Giải thích các bước giải:

    |3x-2|=5

    trường hợp 1 :

    3x – 2 = 5

    3x       = 5 + 2

    3x       = 7

      x        = 7 : 3

      x        = $\frac{7}{3}$ 

    trường hợp 2 :

    3x – 2 = -5

    3x       = -5 + 2

    3x       = -3

     x        = -3 : 3

      x       = -1

    vậy x ∈ { $\frac{7}{3}$ ; -1 }

    $\frac{3}{4}$+$\frac{1}{4}$x=-2

                          $\frac{1}{4}$x = -2 – $\frac{3}{4}$

                          $\frac{1}{4}$x = $\frac{-11}{4}$

                                              x = $\frac{-11}{4}$ : $\frac{1}{4}$

                                              x= -11

    vây x = -11

    ($\frac{2}{3}$) 2 : {-8} – {$\frac{-1}{4}$+$\frac{9}{20}$}:$\frac{9}{5}$

    =$\frac{4}{9}$ . $\frac{-1}{8}$ – { $\frac{-5}{20}$ + $\frac{9}{20}$ . $\frac{5}{9}$

    = $\frac{-4}{72}$ – $\frac{1}{5}$ . $\frac{5}{9}$

    = $\frac{-1}{18}$ – $\frac{2}{18}$

    = $\frac{1}{18}$

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