a) x^2+4x+3= x^2+x+3x+3= x(x+1)+3(x+1)= (x+1)(x+3)
b) ca expresia E sa aiba sens, trebuie ca x^2+5x+6#0,
adica (x+2)(x+3)#0, x#-2, x#-3
x^2+5x+6= x^2+2x+3x+6= x(x+2)+3(x+2)= (x+2)(x+3)
x^2+3x+2= x^2+x+2x+2= x(x+1)+2(x+1)= (x+1)(x+2)
(x^2+4x+3)(x^2+3x+2)= (x+1)(x+3)(x+1)(x+2)= [(x+1)^2](x+2)(x+3)
E(x)= {[(x+1)^2](x+2)(x+3)}/[(x+2)(x+3)]=(x+1)^2 >=0, (E(x) este patrat perfect, pt orice x€R-{-3,-2})
