Question 1061073
.
Good start is to make a plot.


{{{graph( 330, 330, -5.5, 5.5, -2.5, 5.5,
          3x^4 + 4x^3 + 13x^2 + 16x + 4
)}}}


Plot y = {{{3x^4 + 4x^3 + 13x^2 + 16x + 4}}}



When you will get an idea from the plot, destroy it and solve the problem without it.