Mathématiques

Question

Aide MATHEMATIQUES Urgent !!!!

Résoudre les équations suivantes:

a) (3x - 2)(4x + 7) = -14
b) (3x - 2)(4x + 7) = 0
c) (3x - 2)(4x + 7) = 0
d) (7x - 12)(2x + 2) - (4x + 6)(7x - 12) = 0

Merci a ceux ou celles qui m'aideront :)

1 Réponse

  • a) (3x - 2)(4x + 7) = -14
    a = 12x² +21x -8x-14 +14 =0
    a = 12x² +13x = 0
    x(12x+13) = 0

    soit x = 0    soit 12x+13 =0
                              12x = -13
                                  x = -13/12

    b) (3x - 2)(4x + 7) = 0

    3x-2 =0                     ou 4x+7 =0
    3x =2                            4x = -7
    x = -2/3                           x = -7/4

    c) (3x - 2)(4x + 7) = 0

    c est la meme que la b

    d) (7x - 12)(2x + 2) - (4x + 6)(7x - 12) = 0
    (7x-12)(2x+2-4x-6) =0
    (7x-12)(-2x-4) = 0

    7x -12 =0                                  -2x-4 = 0
    7x =12                                           -2x = 4
    x = 12/7                                             x = 4/-2 = -2

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