f(x) = -2/(x-7)

We will take steps to find the tangent line to the graph offat the point (42/3)

(a) Let (xf(x)) be a point on the graph offwithx=4. The slope of the (secant) line joining the two points (42/3) and (xf(x)) can be simplified to the form a/(x-7) whereAis a constant. FindA.

(b) By considering the slope of the secant line asxapproaches 4 , find the slope of the tangent line to the graph offat the point (42/3)

(c) Find the equation of the tangent line to the graph offat the point (42/3). Write your answer in the formy=mx+b.

No clue how to find A, first of all. I'm struggling with the rest obviously too or I wouldnt have posted it, but I'm trying to go one step at a time here. If you can help with all of it, that's great too though.