Résoudre les équations suivantes : Merci d'avance ! A : (3x -4) (7x+ 9) = 0 B : (x +3 ) (-4x + 1) - (x+ 3) (-3x +4) = 0 C : 49x² = 144 D : (-6x + 7) = 64

Bonjour !

A : (3x -4) (7x+ 9) = 0 EPN

3x - 4 = 0 ou 7x + 9 = 0

3x = 4 ou 7x = -9

x = 4/3 ou x = -9/7

S = { -9/7 ; 4/3}

B : (x + 3)(-4x + 1) - (x + 3) (-3x + 4) = 0

<=> (x + 3)(-4x + 1 - (-3x + 4)) = 0

<=> (x + 3)(-4x + 1 + 3x - 4) = 0

<=> (x + 3)(-x - 3) = 0 EPN

x+3 = 0 ou -x -3 = 0

x = -3 ou x = -3

S = {-3}

C : 49x² = 144

<=> 49x² - 144 = 0

<=> (7x - 12)(7x + 12) = 0 EPN

7x - 12 = 0 ou 7x + 12 = 0

7x  = 12 ou 7x = -12

x = 12/7 ou x = -12/7

S = {-12/7 ; 12/7}

D : (-6x + 7) = 64

<=> -6x = 64 - 7

<=> -6x = 57

<=> 6x = -57

<=> x = -57/6

<=> x = -19/2

S = {-19/2}

Voilà !

Réponse:

bonjour comment allez-vous ?