Substitute the letters S, E and N by valid digits to satisfy the following alphametic equation.
(SEEN)Base 8 - (SEEN)Base 5
= (SEEN)Base 7
NOTE: S is NOT zero.
Since 5 is one of the bases, 0 <= S, E, N <= 4, with the additional constraint (given) that S >= 1.
Thus, from the given equation:
S*(8^3 - 5^3) + E*(8^2 + 8 - 5^2 - 5) =S*7^3 + E*(7^2 + 7) + N
which eventually simplifies to: 44S = 14E + N
By inspection, solutions are: (S, E, N) = (1, 3, 2), (2, 6, 4)