Answer:
By definition it follows that
[tex]x \in (A \cap B) \cup(A \cap C)\\[/tex]
Step-by-step explanation:
[tex]\text{if} \,\,\,\,\, x \in A \cap (B \cup C)[/tex]
by definition
[tex]x\in A \,\,\,\,\,\,\,\, \text{and} \,\,\,\,\,\,\,\, x \in (B \cup C). \\ \text{therefore} \,\,\,\,\,x\in A \,\,\,\,\, \text{and} \,\,\,\,\, x\in B \,\,\,\,\, \text{or} \,\,\,\,\,\, x\in \text{C}[/tex]
Then it follows that
[tex]x \in (A \cap B) \cup(A \cap C)\\[/tex]
The other side is pretty much the same.