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

Toán Lớp 7: | 3x – 2 |+ 2/3 = 5/4 – 2/3 : x +5/8 = 7/12 (2x + 3)² =25

Tháng Tư 30, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: | 3x – 2 |+ 2/3 = 5/4
– 2/3 : x +5/8 = 7/12
(2x + 3)² =25

Comments ( 2 )

  1. truonganhthi
    truonganhthi
    30 Tháng Tư, 2022 at 8:27 sáng
    Reply
    | 3x – 2 |+ 2/3 = 5/4
    | 3x – 2 |=7/12
    3x-2=7/12     hoặc  3x-2=-7/12
    3x=31/12                3x=17/12
    x=31/36                   x=17/36
    vậy x∈{31/36,17/36}
    – 2/3 : x +5/8 = 7/12
    – 2/3 : x=-1/24
    x=- 2/3 :-1/24
    x=16
    vậy x=16
    (2x + 3)² =25
    ⇒2x+3=5 hoặc 2x+3=-5
      2x=2                2x=-8
       x=1                   x=-4
    vậy x∈{1,-4}
     

  2. tonhu12
    tonhu12
    30 Tháng Tư, 2022 at 8:27 sáng
    Reply
    Lời giải chi tiết:
    a) |3x-2|+2/3=5/4
    =>|3x-2|=5/4-2/3
    =>|3x-2|=7/12
    =>\(\left[ \begin{array}{l}3x-2=\dfrac{7}{12}\\3x-2=-\dfrac{7}{12}\end{array} \right.\)
    =>\(\left[ \begin{array}{l}3x=\dfrac{7}{12}+2\\3x=-\dfrac{7}{12}+2\end{array} \right.\)
    =>\(\left[ \begin{array}{l}3x=\dfrac{31}{12}\\3x=\dfrac{17}{12}\end{array} \right.\)
    =>\(\left[ \begin{array}{l}x=\dfrac{31}{12}:3\\x=\dfrac{17}{12}:3\end{array} \right.\)
    =>\(\left[ \begin{array}{l}x=\dfrac{31}{36}\\x=\dfrac{17}{36}\end{array} \right.\)
    Vậy x∈{31/36;17/36}
    b) -2/3:x+5/8=7/12
    =>-2/3:x=7/12-5/8
    =>-2/3:x=-1/24
    =>x=-2/3:(-1/24)
    =>x=16
    Vậy x=16
    c) (2x+3)^2=25
    =>\(\left[ \begin{array}{l}2x+3=5\\2x+3=-5\end{array} \right.\)
    =>\(\left[ \begin{array}{l}2x=5-3\\2x=-5-3\end{array} \right.\)
    =>\(\left[ \begin{array}{l}2x=2\\2x=-8\end{array} \right.\)
    =>\(\left[ \begin{array}{l}x=2:2\\x=-8:2\end{array} \right.\)
    =>\(\left[ \begin{array}{l}x=1\\x=-4\end{array} \right.\)
    Vậy x=1 hoặc x=-4

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

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