Answer:
[tex]-2x^3+4x[/tex]
Step-by-step explanation:
I am assuming that the functions are:
[tex]f(x)=2x\\\\g(x)=-2x^3+2x[/tex]
-----------------------
[tex]f(x)+g(x)\\\\2x+-2x^3+2x\\\\2x+2x+-2x^3\\\\4x+-2x^3\\\\\boxed{-2x^3+4x}[/tex]
Hope this helps you!