Answer
$3\log_2{(2y-4)}$
Work Step by Step
RECALL:
(1) Product Property of Logarithms:
$\log_a{mn}=\log_a{m} + \log_a{n}$
(2) Quotient Property of Logarithms:
$\log_a{\frac{m}{n}}=\log_a{m} - \log_a{n}$
(3) Power Property of Logarithms:
$\log_a{m^n}=n\log_a{m}$
Use the Power Property to obtain:
$$\log_2{(2y-4)^3}=3\log_2{(2y-4)}$$