[tex]ax^2+bx+c=0\\\\x_1,\ x_2-the\ roots\\\\x_1+x_2=\dfrac{-b}{a}\\-------------------------\\\text{We have}\ 3x^2+11x-4=0\\\\a=3,\ b=11,\ c=-4\\\\\text{Substitute:}\\\\x_1+x_2=\dfrac{-11}{2(3)}=-\dfrac{11}{6}\\\\Answer:\ \boxed{-\dfrac{11}{6}}[/tex]
