To simplify the expression \( 13^{-5} \cdot 13^{-11} \) and express it with positive exponents, we can use the properties of exponents. Specifically, we apply the rule that states \( a^m \cdot a^n = a^{m+n} \).
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First, we combine the exponents: \[ 13^{-5} \cdot 13^{-11} = 13^{-5 + (-11)} = 13^{-16}. \]
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Now, to express \( 13^{-16} \) with a positive exponent, we use the property that states \( a^{-n} = \frac{1}{a^n} \): \[ 13^{-16} = \frac{1}{13^{16}}. \]
Now let's look at the provided options:
- \( \frac{1}{26^6} \)
- \( \frac{1}{26^{16}} \)
- \( \frac{1}{13^{16}} \)
- \( \frac{1}{13^6} \)
Among the options, \( \frac{1}{13^{16}} \) matches our simplified expression. Thus, the answer is:
\( \frac{1}{13^{16}} \).