Răspuns :
= (x/2)^2 + 2*x/2 * 3 + 3^2 = (x/2 + 3)^2 = (x/2 + 3)(x/2 + 3)
1/4x^2+3x+9=
(x^2+12x+36)/4=
(x^2+6x+6x+36)/4=
[x(x+6)+6(x+6)]/4=
(x+6)^2/4=
[(x+6)/2]^2
(x^2+12x+36)/4=
(x^2+6x+6x+36)/4=
[x(x+6)+6(x+6)]/4=
(x+6)^2/4=
[(x+6)/2]^2