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

Toán Lớp 6: Tìm x , biết 42 + 8 ( 13- x) = 122 b 7( x – 4) =14 . 3mũ2

Toán Lớp 6: Tìm x , biết
42 + 8 ( 13- x) = 122
b 7( x – 4) =14 . 3mũ2

Comments ( 2 )

  1. Giải đáp:
    $\text{a) 42 + 8(13 – x) = 122}$
    ⇔ $\text{8(13 – x) = 122 – 42 = 80}$
    ⇔ $\text{13 – x = 80 ÷ 8 = 10}$
    ⇔ $\text{x = 13 – 10}$
    ⇒ $\text{x = 3}$
    $\text{b) 7(x – 4) =14 . 3}$$^{2}$ 
    ⇔ $\text{7(x – 4) = 7.2.3²}$
    ⇔ $\text{ x – 4 = 2.3}$$^{2}$
    ⇔ $\text{x – 4 = 18}$
    ⇔ $\text{x = 18 + 4}$
    ⇒ $\text{x = 22}$
     #Ling

  2. a)
    42 + 8(13 – x) = 122
    ⇒ 8(13 – x) = 122 – 42 = 80
    ⇒ 13 – x = 80 ÷ 8 = 10
    ⇒ x = 13 – 10 = 3
    b)
    7( x – 4) =14 . 3²
    ⇒ 7( x – 4) =7 . 2 . 3²
    ⇒ x – 4 = 2 . 3² = 2 . 9 = 18
    ⇒ x = 18 – 4 = 14
     
     

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

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