Explain why `7xx11xx13+13` and `7xx6xx5xx4xx3xx2xx1+5` are composite numbers.

Explanation

To determine why the expressions \(7 \times 11 \times 13 + 13\) and \(7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1 + 5\) are composite numbers, we will analyze each expression step by step.

### Step 1: Analyze the first expression \(7 \times 11 \times 13 + 13\)

1. **Factor out the common term**:
\[ 7 \times 11 \times 13 + 13 = 13(7 \times 11 + 1) \]
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