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

Toán Lớp 6: Tìm x : ( 2x + 3 ) chia hết cho ( x – 1)

Toán Lớp 6: Tìm x : ( 2x + 3 ) chia hết cho ( x – 1)

Comments ( 2 )

  1. Tham khảo:

    ( 2x + 3 ) \vdots ( x – 1 )

    2x – 2 + 5 \vdots x – 1

    2(x – 1 ) + 5 \vdots x – 1

    <=> 2( x – 1 ) \vdots x – 1

    => 5 \vdots x – 1

    => x – 1 \in Ư(5) = { -5; -1; 1; 5 }

    => x \in { -4; 0; 2; 6 }

  2. ( 2x + 3 ) chia hết cho ( x -1 )

    -> 2x – 2 + 5 chia hết cho x – 1

    -> 2. ( x – 1 ) + 5 chia hết cho x – 1

     Mà 2.( x – 1) chia hết cho x -1

    -> 5 chia hết cho x -1

    -> x-1∈ Ư( 5 ) ={-5,-1, 1,5}

    -> x∈ {-4, 0, 2, 6}

    Mà x bé nhất

    Nên x = -4

     

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