Evaluate.
\[
\log _{2} \frac{1}{8}
\]
\[
\log _{2} \frac{1}{8}=\square
\]
Final Answer: \( \log _{2} \frac{1}{8} = \boxed{-3} \)
Step 1 :Evaluate the expression \( \log _{2} \frac{1}{8} \).
Step 2 :We know that \( \log _{b} a = n \) if and only if \( b^n = a \).
Step 3 :So, we need to find a number \( n \) such that \( 2^n = \frac{1}{8} \).
Step 4 :We know that \( 2^{-3} = \frac{1}{8} \).
Step 5 :Therefore, \( n = -3 \).
Step 6 :So, \( \log _{2} \frac{1}{8} = -3 \).
Step 7 :Final Answer: \( \log _{2} \frac{1}{8} = \boxed{-3} \)