1003055705
Level:
A
Given the sets
\begin{gather*} A = \{1; 2; 3; 4; 5; 6; 7; 8; 9\},\\ B = \{3; 4; 5; 6; 7\},\\ C = \{6; 7; 8; 9; 10; 11; 12\}, \end{gather*}
find the union \( A\cup B\cup C \).
\( \{1; 2; 3; 4; 5; 6; 7; 8; 9;10; 11; 12\} \)
\( \{1; 2; 3; 4; 5; 6; 7; 8; 9\} \)
\( \{6; 7\} \)
\( \{1; 2; 10; 11; 12\} \)
