Răspuns:
a) (x+y)(a^2-b^2)=
(x+y)(a-b)(a+b)
b) x^2(a+b)-y^2(a+b)=
(a+b)(x-y)(x+y)
c)( 7a+2x+1)^2
d) (√3-x+3)^2
