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

Toán Lớp 6: cho A= 2 + 2 mũ 2 + 2 mũ 3 + 2 mũ 4 +-+ 2 mũ 100 chứng tỏ a chia hết cho 3

Toán Lớp 6: cho A= 2 + 2 mũ 2 + 2 mũ 3 + 2 mũ 4 +….+ 2 mũ 100
chứng tỏ a chia hết cho 3

Comments ( 2 )

  1. $\text{ A = 2 + $2^2$ + $2^3$ + $2^4$ + … + $2^{100}$ }$
    $\text{ A = ( 2 + $2^2$ ) + ( $2^3$ + $2^4$ ) + … + ( $2^{99}$ + $2^{100}$ ) }$
    $\text{ A = 2. ( 1 + 2 ) + $2^3$. ( 1 + 2 ) + … + $2^{99}$. ( 1 + 2 ) }$
    $\text{ A = 2. 3 + $2^3$. 3 + … + $2^{99}$. 3 }$
    $\text{ A = 3. ( 2 + $2^3$ + … + $2^{99}$ )  $\vdots$ 3      ( đpcm ) }$
     

  2. Giải đáp+Lời giải và giải thích chi tiết:
     A=2+2^2+2^3+2^4+…+2^100
    A=(2+2^2)+(2^3+2^4)+…+(2^99+2^100)
    A=(2+4)+2^2(2+2^2)+…+2^98(2+2^2)
    A=6+2^2 . 6+…+2^98 . 6
    A=6(1+2^2+…+2^98)
    Vì 6 \vdots 3
    <=> 6(1+2^2+…+2^98) \vdots 3
    => A \vdots 3
    Vậy A \vdots 3

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

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