Answer
Odd
Work Step by Step
If $f(-x)=f(x)$ then the function is even.
If $f(-x)=-f(x)$ then the function is odd.
If $f(-x)\neq f(x)$ and $f(-x)\neq -f(x)$ then the function is neither odd nor even.
$$f(x)=-x^3+2x$$ $$f(-x)=-(-x)^3+2(-x)=x^3-2x=-(-x^3+2x)=-f(x)$$
Hence, it is odd.
