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

Toán Lớp 7: Tìm x biết a. |5(2 x+3)|+|2(2 x+3)|+|2 x+3|=16

Toán Lớp 7: Tìm x biết
a. |5(2 x+3)|+|2(2 x+3)|+|2 x+3|=16

Comments ( 2 )

  1. Giải đáp:
    x=-0,5 hoặc x=-2,5.
    Lời giải và giải thích chi tiết:
    a)|5(2x+3)|+|2(2x+3)|+|2x+3|=16
    <=>5|2x+3|+2|2x+3|+|2x+3|=16
    <=>8|2x+3|=16
    <=>|2x+3|=2
    <=>[(2x+3=2),(2x+3=-2):}
    <=>[(2x=-1),(2x=-5):}
    <=> \(\left[ \begin{array}{l}x=-0,5\\x=-2,5\end{array} \right.\) 
    Vậy x=-0,5 hoặc x=-2,5.

  2. Giải đáp:
    $\\$
    |5 (2x+3) | + |2 (2x+3) | + |2x+3|=16
    -> 5 |2x+3| + 2 |2x+3| + 1 |2x+3|=16
    -> (5+2+1) |2x+3| =1 6
    -> 8 |2x+3|=16
    -> |2x+3|=16÷ 8
    -> |2x+3|=2
    -> \(\left[ \begin{array}{l}2x+3=2\\2x+3=-2\end{array} \right.\) 
    -> \(\left[ \begin{array}{l}2x=2-3\\2x=-2-3\end{array} \right.\) 
    -> \(\left[ \begin{array}{l}2x=-1\\2x=-5\end{array} \right.\) 
    -> \(\left[ \begin{array}{l}x=-1÷2\\x=-5÷2\end{array} \right.\) 
    -> \(\left[ \begin{array}{l}x=\dfrac{-1}{2}\\x=\dfrac{-5}{2}\end{array} \right.\) 
    Vậy x=(-1)/2 hoặc x=(-5)/2
     

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