If X = {4<sup>n</sup> - 3n - 1, n ∈ N} and Y = {9n - 9, n ∈ N}, then X ∪ Y is equal to
Step-by-step Solution:
\[ X = \{0, 9, 54, \dots\} \] \[ Y = \{0, 9, 18, 27, \dots\} \] Hence, \( X \) is a subset of \( Y \): \[ X \subseteq Y \] Therefore, the union of \( X \) and \( Y \) is: \[ X \cup Y = Y \]