This is from SICP Video Lectures, Lecture 2a around the 39:51 mark.

```
(DEFINE (SQRT X)
   (FIXED-POINT
      (AVERAGE-DAMP (LAMBDA Y (/ X Y)))
      1)) 

(DEFINE AVERAGE-DAMP
   (LAMBDA f
      (LAMBDA x (AVERAGE (f x) x))))

```

What does the `x` in the second lambda do in AVERAGE-DAMP and how is it being accessed? I don't understand what exactly is being passed to it.