How to pass a variable and a list in a lisp function

Question

Apologies if this is a beginner question. Harsh comments are welcome. I am learning LISP and got a snippet like the below. It checks a constant value in a list and returns only the elements greater than it.

(defun greaterthanX (l)
  (if l
    (if (> (car l) 5)
      (cons (car l) (greaterthanX (cdr l)))
      (greaterthanX (cdr l))
    )
  )
)

(print(greaterthanx '(1 2 3 4 5 6 7 8 3)))

Output : (6 7 8) 

My question is how do I pass a variable inside the recursive function and modify it instead of passing a constant value (ie. 5 in the above case)?

I am looking for something like this :

(defun greaterthanX (x l)
  (if l
    (if (> (car l) x)
      (cons (car l) (greaterthanX (cdr l)))
      (greaterthanX (cdr l))
    )
  )
)

(print(greaterthanx '5 '(1 2 3 4 5 6 7 8 3)))

Answer 1

you would additionally pass the x value in the two recursive calls to greaterthanX:

CL-USER 5 > (defun greater-than-x (x l)
              (if (consp l)
                  (if (> (first l) x)
                      (cons (first l)
                            (greater-than-x x (rest l)))
                    (greater-than-x x (rest l)))))
GREATER-THAN-X

CL-USER 6 > (print (greater-than-x 5 '(1 2 3 4 5 6 7 8 3)))

(6 7 8)   ; printed
(6 7 8)   ; repl output