Mathématiques

Question

On donne f(x) = (3x + 2)² -9
Résoudre les équations f(x) =0 ; f(x) = -9; f(x) =-5

1 Réponse


  • (3x+2)²-9

    (3x+2)²-3²

    (3x+2-3)(3x+2+3)

    (3x-1)(3x+5)

    f(x) =0


    3x-1 =0                        3x+5 =0

    x =1/3                            x = -5/3

    f(x) = -9

    3x-1 = -9                                3x+5 = -9

    3x = -8                                    3x = -14

    x= -8/3                                       x = -14/3


    f(x) = -5

    3x-1 = -5                         3x+5 = -5

    3x = -4                               3x = -10

    x= - 4/3                                 x = -10/3


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