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

Toán Lớp 6: Tìm n$\in$$\mathbb{Z}$ a/2-n$\vdots$n+2

Toán Lớp 6: Tìm n$\in$$\mathbb{Z}$
a/2-n$\vdots$n+2

Comments ( 2 )

  1.  a, 2 – n vdots n + 2
    ⇔ (-1) . ( n + 2 ) + 4 vdots n + 2
    ⇔ 4 vdots n + 2 ( bởi vì (-1) . ( n + 2 ) vdots n + 2 )
    ⇒ n + 2 ∈ Ư(4) = { ±1; ±2; ±4 }
    -Ta có: bảng sau:  ( ảnh )
         Vậy x ∈ { -3; -1; -4; 0; -6; 2 }
     

    toan-lop-6-tim-n-in-mathbb-z-a-2-n-vdots-n-2

  2. Ta có : 2 – n vdots n + 2
               n + 2 vdots n + 2
    ⇔ ( n + 2 ) + ( 2 – n ) vdots n + 2
    ⇔ 4 vdots n + 2
    ⇔ n + 2 ∈ Ư( 4 ) = { 1 ; 2 ; 4 ; – 1 ; – 2 ; – 4 }
    ⇔ n ∈ { – 1 ; 0 ; 2 ; – 3 ; – 4 ; – 6 }
    Vậy , n ∈ { – 1 ; 0 ; 2 ; – 3 ; – 4 ; – 6 } .

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