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

Toán Lớp 7: 1) 2/5x + 3/7 = -4/5 2) |2x – 2| + 2/3 = 5/4 – giúp mình với ạ mình đang cần gấp !!

Toán Lớp 7: 1) 2/5x + 3/7 = -4/5
2) |2x – 2| + 2/3 = 5/4
– giúp mình với ạ mình đang cần gấp !!

Comments ( 2 )

  1. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    1) 2/5+ x= -4/5
    x= -4/5- 2/5
    x= -6/5
    2) |2x- 2|+ 2/3= 5/4
    |2x- 2|= 7/12
    2x- 2= 7/12  hoặc 2x- 2= -7/12
    2x= 31/12              2x= 17/12
    x= 31/24                 x= 17/24
     

  2. Answer
    1) 2/5x + 3/7 = {-4}/5
    => 2/5x = -4/5 – 3/7
    => 2/5x = -43/35
    => x = -43/35 : 2/5
    => x = -43/14
    Vậy x = -43/14
    _______________________
    2) |2x – 2| + 2/3 = 5/4
    => |2x – 2| = 5/4 – 2/3
    => |2x – 2| = 7/12
    => $\left[\begin{matrix} 2x – 2 = \dfrac{7}{12}\\ 2x – 2 = \dfrac{-7}{12}\end{matrix}\right.$
    => $\left[\begin{matrix} 2x = \dfrac{7}{12} + 2\\ 2x = \dfrac{-7}{12} + 2\end{matrix}\right.$
    => $\left[\begin{matrix} 2x = \dfrac{31}{12}\\ 2x = \dfrac{17}{12}\end{matrix}\right.$
    => $\left[\begin{matrix} x = \dfrac{31}{12} : 2\\ x = \dfrac{17}{12} : 2\end{matrix}\right.$
    => $\left[\begin{matrix} x = \dfrac{31}{24}\\ x = \dfrac{17}{24}\end{matrix}\right.$
    Vậy x \in {31/24 ; 17/24}

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