bonjour qlq pourrait m'aider a résoudre ces equations merci 1) (3x+4)^2 - 9 = 0 2) (7x+1)(4x-3) - (7x+1)(3-5x) = 7x+1 3) 2x/(x+1) - x^2+1/(x^2+x) - 1 = 0

Bonjour

1) (3x+4)^2 - 9 = 0

(3x+4-3)(3x+4+3) = 0

(3x+1)(3x+7) = 0

3x+1 = 0

X = -1/3

3x + 7 = 0

X = -7/3

2) (7x+1)(4x-3) - (7x+1)(3-5x) = 7x+1

2) (7x+1)(4x-3) - (7x+1)(3-5x) -( 7x+1) =0

(7x+1)(4x-3-3+5x-1) = 0

(7x+1)(8x -7) = 0

7x +1 = 0

X = -1/7

8x-7 = 0

X = 7/8

bonjour

1) ( 3 x + 4)² - 9  = 0

  ( 3 x + 4 - 3) ( 3 x + 4 + 3) = 0

  ( 3 x + 1) ( 3 x + 7) = 0

  soit  3 x + 1 = 0 et x  = - 1/3

  soit 3 x + 7 = 0 et  x = - 7/3

2) ( 7 x + 1) ( 4 x - 3) - ( 7 x + 1) ( 3 - 5 x ) = 7 x + 1

   ( 7 x  + 1 ) ( 4 x - 3 - 3 + 5 x ) - ( 7 x + 1) = 0

   ( 7 x + 1  ) ( 9 x - 6 - 1 ) = 0

   ( 7 x + 1) ( 9 x - 7 ) = 0

  x = - 1/7 ou  7/9

3 ) 2 x / ( x + 1) - (x² + 1 ) / x² + x ) - 1 = 0

pour ceci, il faut faire un tableau de signes , l'as tu appris ?