x, y and z (in this order), with x < y < z, are three positive integers in arithmetic sequence that satisfy this set of alphametic equations.
y4 - x4 = NEWS, and
z4 - y4 = LESS.
where, each of the capital letters in bold represents a different decimal (base 10) digit from 0 to 9.
Determine all possible value(s) of the triplet (x, y, z).
What are the possible four digit number(s) that represent WELL?
Note: Neither L nor N is zero.