The mistake I made on this question was simply a misconception/misreading of the question. I originally thought that it was asking what three bases COULD be a valid representation for the number 1342 (even though the not is even italicized). Using the (b-1) rule, we know that a base can only represent digits one less than the base number. Therefore, since a 1, 2, 3, and 4 are present, we could not use any of these as the base for the number 1342. As a result, we are able to represent bases that are greater than 4 in a valid way for the number 1,342. Above is the work shown for three bases (5,6,7) that can validally represent the number. I then converted the base 5, 6 and 7 numbers to numbers in base 10. From this mistake, I learned to definitely double, triple read the question being asked. This was a simple question that I just misinterpreted.