Respuesta :

The notation [tex]B \cap C[/tex] means "B intersect C" telling you to look at the intersecting, or overlapping, region of the Venn Diagram. This is where the common values that are found in BOTH set B and set C. 

The values {3, 5, 7} are in both set B and set C.

So that is why [tex]B \cap C = \{3, 5, 7\}[/tex]