Show that `AB+bar(AB)` is always 1.

Explanation

To show that \( AB + \overline{AB} = 1 \), we can follow these steps:

### Step 1: Define the Variables
Let \( x = AB \). Then, we can express the complement of \( x \) as \( \overline{x} = \overline{AB} \).

### Step 2: Understand the Values of \( x \)
The value of \( x \) (which is \( AB \)) can either be 0 or 1:
- If \( AB = 0 \), then \( A \) and \( B \) are not both true.
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