bonjour pouvez vous m'aider svp? voici l'exo: on considère l'expression f(x)=(5x-3)au carré-(2x+1)(5x-3) 1 developper puis reduire f(x) 2 factoriser f(x) 3 reso

1) Développement
f(x) = (5x - 3)² - (2x + 1) ( 5x - 3)
f(x) = (5x)² - 2 x 5x x3 + 3² - [ 10x² - 6x + 5x - 3]
f(x) = 25x² -30x + 9 - [ 10x² - x - 3]
f(x) = 25x² - 30x + 9 - 10x² + x + 3
f(x) = 15x² - 29x + 12

2) Factorisation
f(x) = (5x - 3)² - (2x + 1) ( 5x - 3)
f(x) = (5x - 3)(5x - 3) - ( 2x + 1)(5x - 3)
f(x) = ( 5x - 3) [ 5x - 3 - 2x - 1 ]
f(x) = (5x - 3) (3x - 4)

3) f(x) = 0
f(x) = ( 5x - 3) ( 3x - 4)
f(x) = ( 5 x 0 - 3)( 3x0 - 4)
f(x) =  (- 3) x ( - 4)
f(x) = 12

4) f(x) = 12
   f(x) = (5x - 3)(3x - 4)
   f(x) =  ( 5 x 12 - 3)(3 x 12 - 4)
   f(x) = ( 60 - 3)( 36 - 4)
   f(x) = 57 x 32
   f(x) = 1824