svp aidez moi c'est exercice 2 , merci d'avance

Exercice 2 :

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

G = (2x + 3)² - 36
G = (2x + 3)² - 6²
G = (2x + 3 - 6) (2x + 3 + 6)
G = (2x - 3) (2x + 9)