N is a 4-digit positive integer, whose last digit is not zero, and which does not contain any leading zeros.
R(N) is the four-digit integer obtained by reversing the digits of N; for example, R(4386) = 6834
Determine all values of N that satisfy: R(N) = 4N + 3
The 1st digits is clearly 1, forcing last digit to be 7.
Therefore we have to find x and y in the concatenation 1xy7.
the above reduces to x=(99+2y)/13
solvable in integers only as y=9 and x=9
My remark (at most d2) was flatly ignored.
Edited on July 27, 2015, 9:42 am