Sagot :
bonjour,
f (x) = ( x + 3 )² - ( 2 x + 1 ) (x + 3)
f (x) = x² + 6 x + 9 - ( 2 x² + 6 x + x + 3)
f (x) = x² + 6 x + 9 - 2 x² - 7 x - 3
f (x) = - x² - x + 6
f ( 2) = - ( 2)² - ( -2) + 6 = 4 + 2 + 6 = 12
A (0) = 0 - 0 + 6 donc A ∉ courbe
B ( -1) = - ( - 1 )² - ( -1) + 6 = - 1 + 1 + 6 = 6
B ( - 1 : 6 )
f (x) = 0
( x + 3 ) ( x + 3 - 2 x - 1 ) = 0
( x + 3 ) ( x + 2 ) = 0
donc x = - 3 ou - 2
f (x) = - 6
- x² - x + 6 = - 6
- x² - x = 0
x ( - x - 1 ) = 0
x = 0 ou - 1
f(x) > 0 = tu as la réponse dans les calculs au dessus