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

Toán Lớp 7: Tìm x biết A) 6,5 – 9/4 :|x + 1/3| =2 B) 11/4 + 3/2 : |4x – 1/5|=7/2

Home/ Toán Lớp 7: Tìm x biết A) 6,5 – 9/4 :|x + 1/3| =2 B) 11/4 + 3/2 : |4x – 1/5|=7/2

Toán Lớp 7: Tìm x biết A) 6,5 – 9/4 :|x + 1/3| =2 B) 11/4 + 3/2 : |4x – 1/5|=7/2

Tháng Tám 17, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: Tìm x biết
A) 6,5 – 9/4 :|x + 1/3| =2
B) 11/4 + 3/2 : |4x – 1/5|=7/2

Comments ( 2 )

  1. phuongthuydung
    phuongthuydung
    17 Tháng Tám, 2022 at 7:55 sáng
    Reply
    a) 6,5 – 9/4 : | x  +1/3| = 2
    => 9/4 : | x  +1/3 | = 6,5 – 2 = 4,5 = 9/2
    => | x + 1/3| = 9/4 : 9/2 = 1/2
    =>\(\left[ \begin{array}{l}x + 1/3 = 1/2\\x + 1/3 = -1/2\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=1/6\\x=-5/2\end{array} \right.\) 
    b) 11/4 + 3/2 : | 4x – 1/5| = 7/2
    => 3/2 : | 4x – 1/5| = 7/2 – 11/4 = 3/4
    => | 4x – 15| = 3/2 : 3/4 = 2
    =>\(\left[ \begin{array}{l}4x -15 = 2\\4x – 15 = -2\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}4x=17\\4x=13\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=17/4\\x=13/4\end{array} \right.\) 
    Vậy x ∈ { 17/4 ; 13/4 }
     

  2. huongtructram
    huongtructram
    17 Tháng Tám, 2022 at 7:54 sáng
    Reply
    $\\$
    a,
    6,5 – 9/4 : |x+1/3|=2
    -> 9/4 : |x+1/3| = 6,5 – 2
    -> 9/4 : |x+1/3|=9/2
    ->  |x+1/3|=9/4 : 9/2
    ->|x+1/3|=1/2
    TH1 :
    x+1/3=1/2
    ->x=1/2-1/3
    ->x=1/6
    TH2 :
    x+1/3=(-1)/2
    ->x=(-1)/2-1/3
    ->x=(-5)/6
    Vậy x=1/6 hoặc x=(-5)/6
    $\\$
    b,
    11/4 + 3/2 : |4x-1/5| = 7/2
    -> 3/2 : |4x-1/5| = 7/2 – 11/4
    -> 3/2 : |4x-1/5|=3/4
    -> |4x-1/5| = 3/2 : 3/4
    ->|4x-1/5|=2
    TH1 :
    4x-1/5=2
    ->4x=2+1/5
    -> 4x=11/5
    ->x=11/5 : 4
    ->x=11/20
    TH2 :
    4x-1/5=-2
    ->4x=-2+1/5
    ->4x=(-9)/5
    ->x=(-9)/5:4
    ->x=(-9)/20
    Vậy x=11/20 hoặc x=(-9)/20

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

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