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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: tìm x a,8-|1-3x|=3 b,3/5-|x+4/5|=2/5 c,|5/18-x|-1/2=-1/5

Tháng Một 18, 2023 Toán học 2 Comments 0 views

Toán Lớp 8: tìm x
a,8-|1-3x|=3
b,3/5-|x+4/5|=2/5
c,|5/18-x|-1/2=-1/5

Comments ( 2 )

  1. tongtung
    tongtung
    18 Tháng Một, 2023 at 3:43 chiều
    Reply
    a)8-|1-3x|=3
    |1-3x|=8-3
    |1-3x|=5
    =>\(\left[ \begin{array}{l}1-3x=-5\\1-3x=5\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}3x=-6\\3x=-4\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=-2\\x=-4/3\end{array} \right.\) 
    b)3/5-|x+4/5|=2/5
    |x+4/5|=3/5-2/5
    |x+1/4|=1/5
    =>\(\left[ \begin{array}{l}x+1/4=1/5\\x+1/4=-1/5\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=-1/20\\x=-9/20\end{array} \right.\) 
    c)|5/18-x|-1/2=-1/5
    |5/18-x|=-1/5+1/2
    |5/18-x|=3/10
    =>\(\left[ \begin{array}{l}5/18-x=3/10\\5/18-x=-3/10\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=-1/45\\x=26/45\end{array} \right.\) 

  2. kimoanh34
    kimoanh34
    18 Tháng Một, 2023 at 3:43 chiều
    Reply
    8 – |1 – 3x| = 3
    |1 – 3x| = 8 – 3
    |1 – 3x| = 5
    => \(\left[ \begin{array}{l}1 – 3x = 5\\1 – 3x = (-5)\end{array} \right.\)
    => \(\left[ \begin{array}{l}1 – 3x = 1 – 5\\1 – 3x = 1 – (-5)\end{array} \right.\)
    => \(\left[ \begin{array}{l}3x = (-4)\\3x = 6\end{array} \right.\)
    => \(\left[ \begin{array}{l}x = (-4) : 3\\x = 6 : 3\end{array} \right.\)
    => $\left[\begin{matrix} x=\dfrac{-4}{3}\\ x=-2\end{matrix}\right.$  
    Vậy: x ∈ {(-4)/3; (-2)}
    – – – – – –
    3/5 – |x + 4/5| = 2/5
    |x + 4/5| = 3/5 – 2/5  
    |x + 4/5| = 1/5  
    => $\left[\begin{matrix} x+\dfrac{4}{5}=\dfrac{1}{5}\\ x+\dfrac{4}{5}=\dfrac{-1}{5}\end{matrix}\right.$
    => $\left[\begin{matrix} x=\dfrac{1}{5}-\dfrac{4}{5}\\ x=\dfrac{1}{5}-\dfrac{4}{5}\end{matrix}\right.$
    => $\left[\begin{matrix} x=\dfrac{-1}{20}\\ x=\dfrac{-9}{20}\end{matrix}\right.$
    Vậy: x ∈ {(-1)/20; (-9)/20}
    – – – – –
    |5/18 – x| – 1/2 = (-1)/5
    |5/18 – x| = (-1)/5 + 1/2
    |5/18 – x| = 3/10
    => $\left[\begin{matrix} x+\dfrac{5}{18}=\dfrac{3}{10}\\ x+\dfrac{5}{18}=\dfrac{-3}{10}\end{matrix}\right.$
    => $\left[\begin{matrix} x=\dfrac{5}{18}-\dfrac{3}{10}\\ x=\dfrac{5}{18}-\dfrac{-3}{10}\end{matrix}\right.$
    => $\left[\begin{matrix} x=\dfrac{-1}{45}\\ x=\dfrac{26}{45}\end{matrix}\right.$
    Vậy: x ∈ {(-1)/45; 26/45}

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222-9+11+12:2*14+14 = ? ( )

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