It's a LISP programming problems.. I need to make a function !! can you help with any of these questions??

11-a. (car-string n l) :

I need to make car-string function that prints out the first list of length n..........

(car-string 3 (a b c d e)) = (a b c)

(car-string 4 (a b c d e)) = (a b c d)

11-b. (equal-except n l1 l2) : For the two same length list l1,l2 if the number of different letters between two list is same or smaller than n it's T if it's bigger than nil..

I need to make equal except function

(equal-except 2 (a b c d) (b b c c)) = T

(equal-except 3 (a b c d e) (e f g a b) = nil