For any two sets `A\ a n d\ B ,\ ` prove that `AsubB=>AnnB=A`

Explanation

To prove that if \( A \subseteq B \), then \( A \cap B = A \), we will follow these steps:

### Step 1: Show that \( A \cap B \subseteq A \)

To show that \( A \cap B \subseteq A \), we take an arbitrary element \( x \) such that \( x \in A \cap B \). By the definition of intersection, this means that \( x \) is in both sets \( A \) and \( B \).

- Since \( x \in A \cap B \), we have:
- \( x \in A \)
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