6,14,18,19 giúp nhá mai mình ktra rồu!!!

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6,14,18,19 giúp nhá mai mình ktra rồu!!!
6-14-18-19-giup-nha-mai-minh-ktra-rou

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Sapo 6 years 2020-10-28T07:38:23+00:00 2 Answers 191 views 0

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  1. Vodka
    0
    2020-10-28T07:39:36+00:00
    Reply

    Đáp án:

     

    Giải thích các bước giải:

    6) x2+2x+1-y2

    =x2+2.x.1+12-y2

    =(x+1)2-y2

    14) x2-1+2xy+y2

    =x2+2xy+y2-1

    =x2+2.x.y+y2-1

    =(x+y)2-1

    18) a2-b2-6b-9

    =a2(b2+6b+9)

    =a2-(b+3)2

    =(a+b+3)(a-b-3)

    19) 16x2+y2+6y-9

    =16x2-(y2-6y+9)

    =16x2-(y-3)2

    =(16x+y+3)( 16x-y-3)

     

  2. Sigrid
    0
    2020-10-28T07:40:15+00:00
    Reply

    6. $x^2+2x+1-y^2$
    $=(x^2+2x+1)-y^2$

    $=(x+1)^2-y^2$

    $=(x+y+1)(x-y+1)$

    14. $x^2-1+2xy+y^2$

    $=(x^2+2xy+y^2)-1$

    $=(x+y)^2-1$

    $=(x+y+1)(x+y-1)$

    18. $a^2-b^2-6b-9$

    $=a^2-(b^2+6b+9)$

    $=a^2-(b+3)^2$

    $=(a+b+3)(a-b-3)$

    19. $16x^2-y^2+6y-9$

    $=16x^2-(y^2-6y+9)$

    $=(4x)^2-(y-3)^2$

    $=(4x+y-3)(4x-y+3)$.

     

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