Answer:
[tex]x \in \{3, 6, 9 \}[/tex]
Step-by-step explanation:
Given:
[tex]\{x | x = 3n, n \in \mathbb N \}[/tex]
The first three elements of the given set are just the values of [tex]x[/tex] when [tex]n = 1, 2, 3[/tex].
Solving for [tex]x[/tex] when [tex]n = 1[/tex]:
[tex] x = 3n \\ x = 3(1) \\ x = 3[/tex]
Solving for [tex]x[/tex] when [tex]n = 2[/tex]:
[tex] x = 3n \\ x = 3(2) \\ x = 6[/tex]
Solving for [tex]x[/tex] when [tex]n = 3[/tex]:
[tex] x = 3n \\ x = 3(3) \\ x = 9[/tex]
