Bonjour quelqu’un peut-il m’aider svp ?

Réponse de l'exercice 4: (S'il y'a des erreurs, mettez les en commentaire, mais ça m'étonnerait.).

Exercice n°4 :

A = (x+3) (x+1)

=x*x+x*1+3*x+3*1

=x²+x*1+3*x+3*1

=x²+4x+3

B = (x+7) (x+2)

=x*x+x*2+7*x+7*2

=x²+2x+7x+14

=x²+9x+14

C = (x+2) (x-5)

=x*x+x*(-5) +2*x+2*(-5)

=x²+(-5x)+2x+(-10)

=x²-5x+2x-10

=x²-3x-10

D = (x+3) (x-9)

= x*x+x*(-9) +3*x+3*(-9)

= x²+ (-9x)+3x+ (-27)

= x²-9x+3x-27

=x²-6x-27

E = (x+6) (x-8)

= x*x+x*(-8)+6*x+6*(-8)

=x²+(-8x)+6x+(-48)

=x²-8x+6x-48

=x²-2x-48

F = (x-3) (x+4)

= x*x+x*4-3*x-3*4

= x²+4x-3x-12

=x²+x-12

G = (x-7) (x-4)

= x*x+x*(-4)-7*x-7*(-4)

= x²+(-4x)-7x+28

= x²+(-11x)+28

=x²-11x+28

H = (x-1) (x+7)

= x*x+x*7-1*x-1*7

= x²+7x-x-7

= x²+6x-7

I = (2x+7) (3x+8)

= 2x*3x+2x*8+7*3x+7*8

= 6x+2x*8+21x+56

= 8x+21x+56*8

= 29x+ 448