This one is pretty simple in terms that it's just plugging in for f(a) it's going to be your original equation 2x+8. As for f(a+h) your simply going to add the letter h to the original equation so it would look something like this 2x+8+h. For the last one it is a little bit more complicated you're going to subtract what you got for f(a+h) and f(a) but then you are going to have to divide by h. In the end, you should end up with h/h or 1.
