Which of the following is a root of the polynomial function below? F(x)= x+3x? -5x - 4 Ο Α. 4 O O 2 2 o B. 1 B 1 O c. 1.5 Ос 3 3 OD 3 D. 3

Given:
[tex]f(x)=x^3+3x^2-5x-4[/tex]To determine the roots, we let f(x)=0 first:
[tex]x^3+3x^2-5x-4=0[/tex]Next, we find factor of the equation:
[tex]\begin{gathered} x^3+3x^2-5x-4=(x+4)(x^2-x-1)=0 \\ \end{gathered}[/tex]Then, we use quadratic formula for x^2-x-1=0:
We plug in what we know:
Hence,
We also get the x value of x+4=0:
[tex]\begin{gathered} x+4=0 \\ x=-4 \end{gathered}[/tex]Therefore, the answer is: