bonjour
f (x) = 4 ( x + 1 )² - 1
f (x) = 4 ( x² + 2 x+ 1 ) - 1
f (x) = 4 x² + 8 x + 4 - 1
f (x) = 4 x² + 8 x + 3
1. f (x) = (2 x + 1 ) ( 2 x + 3 )
f (x) = 4 x² + 6 x + 2 x + 3 = 4 x² + 8 x + 3
2. f (0) = 3
f ( - 1 ) = 4 ( -1 )² + 8 ( -1) + 3 = 4 - 8 + 3 = - 1
racines de f = - 1/2 et - 3/2
( 2 x + 1 ) ( 2 x + 3 ) = 0
x = - 1/2 ou - 3/2