svp C est urgent c est trop difficile à comprendre pour moi

c = (2x + 5)(3x + 7)
c = 6x² + 14x + 15x + 35
c = 6x² + 29x + 35

d = (5x + 8)(2x - 7)
d = 10x² - 35x + 16x - 56
d = 10x² - 19x - 56

e = (2x - 5)(3x - 2)
e = 6x² - 4x - 15x + 10
e = 6x² - 19x + 10

Exercice 2 :

C = (2x + 5)(3x + 7)
C = 2x * 3x + 2x * 7 + 5 * 3x + 5 * 7
C = 6x² + 14x + 15x + 35
C = 6x² + 29x + 35

D =(5x + 8)(2x - 7)
D = 5x * 2x - 5x * 7 + 8 * 2x - 8 * 7
D = 10x² - 35x + 16x - 56
D  10x² - 19x - 56

E = (2x - 5)(3x - 2)
E = 2x * 3x - 2x * 2 - 5 * 3x + 5 * 2
E = 6x² - 4x - 15x + 10
E = 6x² - 19x + 10