Réponse :
bonjour
1 post = 1 exercice
f (x) = ( 1 + x )² - ( 3 x + 2 ) ( x + 1 )
f (x) = 1 + 2 x + x² - ( 3 x² + 3 x + 2 x + 2 )
f (x) = x² + 2 x + 1 - 3 x² - 5 x - 2
f (x) = - 2 x² - 3 x - 1
f (x) = ( x + 1 ) ( x + 1 - 3 x - 2 )
f (x) = ( x + 1 ) ( - 2 x - 1 )
f (0) = 1 * - 1 = - 1
f ( √5) = - 2 ( √5)² - 3 √5 - 1
f ( √5) = - 10 - 3 √5 - 1 = - 11 - 3 √5
f (x) = 0
( x + 1 ) ( - 2 x - 1 ) = 0
x = - 1 ou - 1/2
f (x) = - 1
- 2 x² - 3 x - 1 = - 1
- 2 x² - 3 x = 0
- x ( 2x + 3 ) = 0
x = 0 ou - 3/2
Explications étape par étape :
