I've been working on this problem for a while and it's got me stumped.

http://img59.imageshack.us/img59/1536/calc1ho7.png

I thought I was doing it right, until in the third column I got Undefined for where x = 2 and f(x) = 4. I don't need the entire column filled it, just a couple values maybe.

What I've been doing is, for example, for the first pairing (1, 1) I plugged in values for the equation winding up with;

(1-4)/(1-2)

-3/-1

3

I got the 4 by going to the x value on the table and looking at the f(x) that matched up with it which was 4. However... I was worried I was making a mistake when I got undefined for (2,4) and then I was positive I'd made a mistake when I tried to find the speed of the car at 2... where it was undefined. We're currently learning about limits and continuity... and I'm having trouble seeing how this ties in as well.

Edit// Probably should have put this in urgent homework help. Sorry.