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

Toán Lớp 8: (-3x+1)(9x^2+1)(-3x-1) mn giúp mk vs

Toán Lớp 8: (-3x+1)(9x^2+1)(-3x-1)
mn giúp mk vs

Comments ( 2 )

  1. $(-3x+1)(9x^2+1)(-3x-1)$
    $=(-3x+1)(-3x-1)(9x^2+1)$
    $=(9x^{2}-1)(9x^2+1)$
    $=81x^4-1$
    (Sử dụng HĐT $A^{2}-B^{2}=(A+B)(A-B)$)
    Xin hay nhất cho nhóm ạ
     

  2. Giải đáp:
    (-3x+1)(9x^2+1)(-3x-1)
    =-(3x-1)(9x^2+1).(-1)(3x+1)
    =(3x-1)(3x+1)(9x^2+1)
    =[(3x)^2-1](9x^2+1)
    =(9x^2-1)(9x^2+1)
    =(9x^2)^2-1
    =81x^4-1

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