Answer: So the set is X > 1, X ⊂ N
so x ∈ X = {2,3,4,5.....}
So the statement is, if x.y ∈ X
then x cant divide (x*y +1)
you can see this using the distributive property in the next way:

where y is a natural, and 1/x is a irrational number, the addition of a natural and a irrational number is an irrational number.
then
is irrational, this means that x does not divide x*y +1.