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

Toán Lớp 7: A)|x-1/2| ≤ 1/3 B)|2x-1/2| > |-1,5| Cần giải gấp

Toán Lớp 7: A)|x-1/2| ≤ 1/3
B)|2x-1/2| > |-1,5|
Cần giải gấp

Comments ( 2 )

  1. |x-1/2|<=1/3
    =>-1/3<=x-1/2<=1/3
    =>1/6<=x<=5/6
    Vậy S={x\inRR|1/6<=x<=5/6}
    |2x-1/2|>|-1,5|
    =>|2x-1/2|>1,5
    Th1: 2x-1/2>1,5
    =>x>1
    Th2: 2x-1/2<-1,5
    =>x<-1/2
    Vậy x>1 hoặc x<-1/2

  2. $\\$
    a,
    |x-1/2| ≤ 1/3
    TH1 :
    x-1/2 ≥ (-1)/3
    -> x ≥ (-1)/3 + 1/2
    -> x ≥ 1/6
    TH2  :
    x-1/2 ≤ 1/3
    ->x ≤ 1/3 + 1/2
    ->x ≤ 5/6
    Vậy x ≥ 1/6 hoặc x ≤ 5/6
    $\\$
    b,
    |2x- 1/2| > |-1,5|
    -> |2x-1/2| > 1,5
    TH1 :
    2x -1/2 < -1,5
    -> 2x < -1,5 + 1/2
    ->2x < -1
    ->x < -1 : 2
    ->x <(-1)/2
    TH2 :
    2x-1/2 > 1,5
    -> 2x > 1,5 + 1/2
    ->2x > 2
    -> x> 2:2
    ->x>1
    Vậy x<(-1)/2 hoặc x>1

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