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

Toán Lớp 6: 2n+4chia hết cho n+1 giúp mình với

Toán Lớp 6: 2n+4chia hết cho n+1 giúp mình với

Comments ( 2 )

  1. $\text{2n+4 $\vdots$ n+1}$
    $\text{$\Rightarrow$ 2 $\vdots$ n+1}$
    $\text{$\Rightarrow$ n+1 ∈ Ư(2)}$
    $\text{Ư(2)={±1,±2}}$
    $\text{TH1 : n+1=1 $\Leftrightarrow$ n=0}$
    $\text{TH2 : n+1=-1 $\Leftrightarrow$ n=-2}$
    $\text{TH3 : n+1=2 $\Leftrightarrow$ n=1}$
    $\text{TH4 : n+1=-2 $\Leftrightarrow$ n=-3}$
    $\text{Vậy để 2n+4 $\vdots$ n+1 thì n={0;-2;1;-3}}$

  2. Ta có
    2n+4=2n+2+2=2(n+1)+2
    Để 2n+4$\vdots$n+1
    => 2$\vdots$n+1
    =>n+1∈$Ư_{2}$ ={±2;±1}
    => n∈{0;-2;1;-3}
     

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

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