How do I do this? Freshman in need of serious help
A={3,6,7,12} B={1,3,5,7,15} C={6,7,11,15}
(A"union"B)"intersection"C
There's no $\displaystyle 11 $ in $\displaystyle A \cup B $ but there is an $\displaystyle 11 $ in $\displaystyle C $. So $\displaystyle A \cup B $ and $\displaystyle C $ do not share $\displaystyle 11 $ as a common element (i.e. the intersection between these two sets does not contain $\displaystyle 11 $).