6x + 1 ≠ 0 ⇒ x≠ - 1/6
este o fractie subunitara
x I -∞ -1/6 ∞
---------------I----------------------------------------------------------------------------------------------------
f(x) I 0 +∞ I -∞ 0
mc mc
f(0) =-5
daca se calculeaza si f' >0 si nu are radacini