Bonjour
On considère C = (2x + 1)² - 49.
a. Factorise C.
C = (2x + 1)² - 49
C = (2x + 1 + 7) (2x + 1 - 7)
C = (2x + 8) (2x - 6)
b. Résous l'équation C = 0.
C = 0
(2x + 8) (2x - 6) = 0
2x + 8 = 0 ou 2x - 6 = 0
2x = - 8 2x = 6
x = - 8/2 = - 4 x = 6/2 = 3.
