bonjour exo maths 3 ème aidez moi svp merci d avance

Bonjour,

Exercice 18 :
a) (7x+1)^2
= 7x*7x + 7x*1 + 7x*1 + 1*1
= 49x^2 +14x+1

b) (x-3)^2
= x*x + x*(-3) + x*(-3) + (-3)*(-3)
= x^2 - 6x+9

c) (1/3 - 3/4a)^2
= 1/3*1/3 + -3/4a * (-3/4a) + 1/3* (-3/4a)
= 1/9 + 9a^2/16 -a/2