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

Toán Lớp 6: c) ∣1/2 – 3x∣ + 21/5 = 32/5 d) 17/2 – ∣2x – 3/4∣ = -7/4 help mik vs

Toán Lớp 6: c) ∣1/2 – 3x∣ + 21/5 = 32/5
d) 17/2 – ∣2x – 3/4∣ = -7/4
help mik vs

Comments ( 2 )

  1. c) |1/2 – 3x| + 21/5 = 32/5
    |1/2 – 3x| = 32/5 – 21/5
    |1/2 – 3x| = 2
    → TH1: 1/2 – 3x = 2 ⇔ 3x = -3/2 ⇔  = -1/2
    → Th2: 1/2 – 3x = -2 ⇔ 3x = 5/2 ⇔ x = 5/6
    d,17/2 – |2x-3/4| = (-7)/4
    |2x-3/4| = 17/2 + 7/4
    |2x-3/4|=41/4
    TH1 : 2x-3/4=41/4 ⇔ 2x=11 ⇔ x = 11/2
    TH2 : 2x-3/4=(-41)/4 ⇔ 2x=(-19)/2 ⇔ x=(-19)/4

  2. $\\$
    c,
    |1/2 – 3x| + 21/5 = 32/5
    -> |1/2 – 3x| =32/5 – 21/5
    -> |1/2 – 3x|=11/5
    Trường hợp 1 :
    -> 1/2 – 3x=11/5
    ->3x=1/2 – 11/5
    ->3x=(-17)/10
    ->x=(-17)/10 : 3
    ->x=(-17)/30
    Trường hợp 2 :
    -> 1/2 – 3x=(-11)/5
    -> 3x=1/2 + 11/5
    ->3x=27/10
    ->x=27/10 : 3
    ->x=27/30
    vậy x=(-17)/30 hoặc x=27/30
    $\\$
    d,
    17/2 – |2x-3/4| = (-7)/4
    -> |2x-3/4| = 17/2 + 7/4
    -> |2x-3/4|=41/4
    Trường hợp 1 :
    -> 2x-3/4=41/4
    ->2x=41/4 + 3/4
    ->2x=11
    ->x=11 :2
    ->x=11/2
    Trường hợp 2 :
    ->2x-3/4=(-41)/4
    ->2x=(-41)/4 + 3/4
    ->2x=(-19)/2
    ->x=(-19)/2 : 2
    ->x=(-19)/4
    Vậy x=11/2 hoặc x=(-19)/4
     

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