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

Toán Lớp 6: a,25 + 3(x-8)+=106 b,3 mũ 2 (x+4)-5 mũ 2 =5.2 mũ 2

Toán Lớp 6: a,25 + 3(x-8)+=106
b,3 mũ 2 (x+4)-5 mũ 2 =5.2 mũ 2

Comments ( 2 )

  1. $\text{a)25 + 3·( x – 8) = 106}$
    $\text{⇒3 · (x – 8) = 106 – 25}$
    $\text{⇒3 · (x – 8) = 81}$
    $\text{⇒x – 8 = 81 ÷ 3}$
    $\text{⇒x – 8 = 27}$
    $\text{⇒x = 27 + 8}$
    $\text{⇒x = 35}$
    $\text{Vậy x = 35}$
    $\text{b)3² · (x + 4) – 5² = 5 · 2²}$
    $\text{⇒9 · (x + 4) – 25 = 5 · 4}$
    $\text{⇒9 · (x + 4) – 25 = 20}$
    $\text{⇒9 · (x + 4) = 20 + 25}$
    $\text{⇒9 · (x + 4) = 45}$
    $\text{⇒x + 4 = 45 ÷ 9}$
    $\text{⇒x + 4 = 5}$
    $\text{⇒x = 5 – 4}$
    $\text{⇒x = 1}$
    $\text{Vậy x = 1}$

  2. a) 25 + 3(x – 8) = 106
    ⇒         3(x – 8) = 106 – 25
    ⇒         3(x – 8) = 81
    ⇒             x – 8 = 81 ÷ 3
    ⇒             x – 8 = 27
    ⇒             x      = 27 + 8
    ⇒             x      = 35
    ___________________________________________
    b) 3^2 (x + 4) – 5² = 5 . 2²
    ⇒ 3^2 (x + 4) – 25 = 20
    ⇒ 3^2 (x + 4)         = 45
    ⇒ 9(x + 4)                 = 45
    ⇒    x + 4                  = 5
    ⇒  x                           = 9
     

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

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