Answer
$\log{\left(\frac{m^4}{n}\right)}$
Work Step by Step
Recall the power property of logarithms (pg. 462):
$\log_b{m^n}=n\log_b{m}$
Thus we have:
$4\log m-\log n=\log m^4-\log n$
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:
$\log m^4-\log n=\log{\frac{m^4}{n}}$