F(x)=3x+5x

It looks like the function \( F(x) = 3x + 5x \) can be simplified. You can combine the like terms:

\[ F(x) = (3 + 5)x = 8x \]

So the simplified version of your function is:

\[ F(x) = 8x \]

If you have any specific questions related to this function or need further assistance, feel free to ask!