Let f(x) = x^2 - 2x.

f(1) = -1     f(8) = 48

find the slope of the line joining  (1,-1)  and  (8,48)   <======   do you know how to do that?

If you knew the answers to A and C.....WHY did you post them???????

For part B....you do it just the same way...with slightly different numbers ...

f(6) = 24

f(6+h) =   h^2 + 12h + 36 - 12-2h = h^2 + 10h + 24

The slope between the points becomes   (y1-y2)  / (x1-x2) 

(h^2+10h+24  -24) / (6+h - 6) =   (h^2 + 10h ) / h     =   h+10              (check my math.....but that is how you do it.....)

For Part D  .....   do you know how to do derivatives ?

f(6) = 24  

find the slope at this point (6) by using the derivative

   f ' (6) =   2x -2   = 10   = m        

   now you have a slope  m = 10    and a point    (6,24)     to derive the equation of the line......

Gamemaster,

You need to start talking about the questions that you post.

I mean you need to discuss what you already think you know and what thoughts you have on the rest.

Just dumping questions is simply NOT cool.

I think you are capable of better.