( a + b )^2 tại sao = a^2 + 2ab + b^2 ạ ??

Question

( a + b )^2 tại sao = a^2 + 2ab + b^2 ạ ??

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Euphemia 4 years 2020-10-13T12:19:30+00:00 2 Answers 100 views 0

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  1. Nho
    0
    2020-10-13T12:20:48+00:00
    Reply

    `( a + b )^2`

    `= ( a + b )( a + b )`

    `= a^2 + ab + ba + b^2`

    `= a^2 + 2ab + b^2`

  2. Ladonna
    0
    2020-10-13T12:21:05+00:00
    Reply

    $(a+b)^2$

    $=(a+b)(a+b)$

    $=a(a+b)+b(a+b)$

    $=a^2+ab+ab+b^2$

    $=a^2+2ab+b^2$

     

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )