Tìm x biết (x – 2)(2x + 4) – 2x(x + 1) = 0

Question

Tìm x biết (x – 2)(2x + 4) – 2x(x + 1) = 0

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Anna 1 năm 2021-07-05T17:45:57+00:00 2 Answers 5 views 0

Answers ( )

  1. maingocquynhnhu
    0
    2021-07-05T17:47:32+00:00
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    $(x-2)(2x+4)-2x(x+1)=0$

    $⇔2(x-2)(x+2)-2x^2-2x=0$

    $⇔2(x^2-4)-2x^2-2x=0$

    $⇔2x^2-8-2x^2-2x=0$

    $⇔-2x-8=0$

    $⇔-2(x+4)=0$

    $⇔x+4=0$

    $⇔x=-4$

    $\text{Vậy $x=-4$}$

  3. thubichdan
    0
    2021-07-05T17:47:44+00:00
    Reply

    Đáp án:

     $x=-4$

    Giải thích các bước giải:

     $(x-2).(2x+4)-2x.(x+1)=0$

    $⇔2x^2-8-2x^2-2x=0$

    $⇔-2x-8=0$

    $⇔-2x=8$

    $⇔x=-4$

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