Réponse :

A= (1-racine de 2)carré

(a-b)2= a2-2ab+b2)

= 1 - 2racine de2 + 2

 =3-2racine de 2

B = (2+ racine de 3)(2- racine de 3)

(a+b)(a-b)= a2-b2

 = 4 - 3 = 1

C = (2racine de3 -4)carré

(a-b)2 = a2 - 2ab+b2

 = 12 - 16racine de 3 + 16

 =28 - 16racine de3

D = (2+ 3racine de 5)carré

(a+b)2 = a2+2ab+b2

 =4 + 12racine de 5 + 45

 =49+ 12racine de