Answer: The set {(3, 6), (4, 8), (5, 10), (3, 1), (6, 12), (7, 10)} is not a function because it violates the condition for a function, which states that for every element in the domain (the set of input values), there can be only one element in the range (the set of output values). In this particular set, the input value 3 has two different output values, 6 and 1. Therefore, the set is not a function.