Write the resulting set using the listing method.
\[
\{1,8,9\} \cup\{1,2,9\}
\]
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. $\{1,8,9\} \cup\{1,2,9\}=$
(Use a comma to separate answers as needed.)
B. $\{1,8,9\} \cup\{1,2,9\}$ is the empty set.
Answer
The union of the two sets \(\{1,8,9\} \cup \{1,2,9\}\) is \(\boxed{\{1,2,8,9\}}\).
Step 1 ：The question is asking for the union of two sets. The union of two sets is a set that contains all the elements from both sets. If an element is in either of the two sets, it will be in the union set.
Step 2 ：In this case, we need to combine the elements from both sets, and remove any duplicates, because in set theory, each element is unique.
Step 3 ：Set 1 is \(\{1,8,9\}\) and Set 2 is \(\{1,2,9\}\).
Step 4 ：The union of the two sets \(\{1,8,9\} \cup \{1,2,9\}\) is \(\boxed{\{1,2,8,9\}}\).
