This appears to meet your conditions:
=IF(ISBLANK(X11),IF(AND(H11="x",K11<=14),"Y",IF(AN D(H11="x",K11=15),"N")),IF(AND(X11="x",H11="x",K1 1=15),"C","Y"))

however, if h11 is blank or contains a value other than x, AND x11 is blank
it returns a FALSE
or
if h11 is blank or contains a value other than x, AND x11 is not blank, L11=Y

if you can give me some idea of what you want to do about non-x values in
h11 or x11, I can refine the formula


"Help with cell function" wrote:

Sorry if this offends anyone, but I need an answer and I already submitted
this question yesterday.
the below formula was close, but not quite.
I only want a C to show up in L6 if a N is going to be the answer, if a Y is
the answer then I need to keep the Y. If X6 is not an x then the answer needs
to stay the same in L6

=IF(H6="x", IF(K6<=14,"Y", IF(X6="x","C","N")), "")