Question

List the first three elements of the set {x|x = 3n, n a positive integer}

Answer 1

Answer:

{3,6,9}

Step-by-step explanation:

first element = 3×1

second element = 3×2

third element = 3×3

Step-by-step explanation:

Answer 2

Answer:

$x \in \{3, 6, 9 \}$

Step-by-step explanation:

Given:

$\{x | x = 3n, n \in \mathbb N \}$

The first three elements of the given set are just the values of $x$ when $n = 1, 2, 3$.

Solving for $x$ when $n = 1$:

$x = 3n \\ x = 3(1) \\ x = 3$

Solving for $x$ when $n = 2$:

$x = 3n \\ x = 3(2) \\ x = 6$

Solving for $x$ when $n = 3$:

$x = 3n \\ x = 3(3) \\ x = 9$