Answer
$\log{\left(\frac{5}{2^k}\right)}$
Work Step by Step
Recall the power property of logarithms (pg. 462):
$\log_b{m^n}=n\log_b{m}$
Thus we have:
$\log 5-k\log 2=\log 5-\log 2^k$
Next, recall the quotient property of logarithms (pg. 462):
$\log_b{\frac{m}{n}}=\log_b{m}-\log_b{n}$
Applying this to our last equation, we get:
$\log 5-\log 2^k=\log{\frac{5}{2^k}}$
