Answer:
[tex]\Large \boxed{\sf \ \ -2x^2-2x+8 \ \ }[/tex]
Step-by-step explanation:
Hello, please consider the following.
[tex](f+g)(x)=f(x)+g(x)=3x+5+(-2x^2-5x+3)\\\\=3x+5-2x^2-5x+3=\large \boxed{-2x^2-2x+8}[/tex]
Hope this helps.
Do not hesitate if you need further explanation.
Thank you