Use the properties of logarithms to expand $\log \frac{z^{7}}{y}$. Each logarithm should involve only one variable and should not have any exponents or fractions. Assume that all variables are positive.

Step 1 ：Given the expression \(\log \frac{z^{7}}{y}\).

Step 2 ：Use the properties of logarithms to expand the expression. The properties of logarithms state that \(\log \frac{a}{b} = \log a - \log b\) and \(\log a^n = n \log a\).

Step 3 ：Applying these properties, the expression \(\log \frac{z^{7}}{y}\) can be expanded to \(- \log y + 7 \log z\).

Step 4 ：Final Answer: The expanded form of \(\log \frac{z^{7}}{y}\) is \(\boxed{- \log y + 7 \log z}\).