Let $A = \{ 2,4,5 \}$ and $B = \{ 6,7,9 \}$ . Find $A \cup \bar { B }$ .
A) $( - \infty , \infty )$
B) $\{ 4,9 \}$
C) $\{ 2,4,5,6,7,9 \}$
D) $\varnothing$

Question

Quizplus · Accepted Answer

First, we need to find the complement of B, denoted by $\bar { B}$:
$$\bar { B} = \{ x \mid x \not\in B \} = \{ 2, 3, 4, 5, 8 \}$$
Then, the union of A and $\bar {B}$ is:
$$A \cup \bar { B } = \{ 2, 4, 5 \} \cup \{ 2, 3, 4, 5, 8 \} = \{ 2, 3, 4, 5, 8 \} \cup \{ 2, 4 ,5\} = \{ 2, 3, 4, 5, 8 \}$$
Therefore, the answer is C: $\{ 2,4,5,6,7,9 \}$.

Let A={2,4,5}A = \{ 2,4,5 \}A={2,4,5} And B={6,7,9}B = \{ 6,7,9 \}B={6,7,9}

Let $A = \{ 2,4,5 \}$ And $B = \{ 6,7,9 \}$