Răspuns :

(a+b)^2=a^2+2ab+b^2  ;
(a-b)^2=a^2-2ab+b^2  ;
 a^2-b^2=(a+b)(a-b) ;
 (a+b+c)^2=a^2+b^2+c^2+2ab+2ac+2bc ;
(a+b)^3=a^3+3a^2b+3ab^2+b^3       ;     
  (a-b)
^3=a^3-3a^2b+3ab^2-b^
a^3+b^3=(a+b)(a^2-ab+b^2)           ;  
     a
^3-b^3=(a-b)(a^2+ab+b^2) ;