[tex](f+g)(x)=x^{2}+3x+5[/tex]
1) In this question, we are dealing algebra of functions. So, let's add them up.
2)
[tex]\begin{gathered} f(x)=3x+5 \\ g(x)=x^2 \\ f(x)+g(x)=3x+5+x^2 \\ (f+g)(x)=x^2+3x+5 \end{gathered}[/tex]
Note that we wrote it in the standard form.
2) Hence, the answer is:
[tex](f+g)(x)=x^{2}+3x+5[/tex]
