a) (5x+2)² - (5x+2)(x-5) = 25x² + 20x + 4 - (5x²-25x+2x-10)

= 25x² + 20x + 4 - 5x² + 23x + 10

= 20x² + 43x + 14

b) le facteur commun est (5x+2) :

<=> (5x+2) (5x+2 - (x-5))

<=> (5x+2) (4x+7)

c)

f(0) = (5(0) + 2) (4(0) + 7) = 2*7 = 14

f(-2) = (5*(-2) + 2) (4*(-2) + 7) = (-10 + 2) (-8 + 7)

= -8 * -1 = 8

Résoudre f(x) = G ??? genre pour G = 0 ?

f(x) = G = 0

(5x+2) (4x+7) = 0

equation produit nul :

5x + 2 = 0 ou 4x + 7 = 0

x = -2/5 ou x = -7/4

Bonne soirée.