Use the Definition of a Logarithm to Solve Logarithmic Equations $\log _ { 9 } \left( x ^ { 2 } - 8 x \right) = 1$

Multiple Choice

Use the Definition of a Logarithm to Solve Logarithmic Equations
Solve the logarithmic equation. Be sure to reject any value that is not in the domain of the original logarithmic
expressions. Give the exact answer.
- $\log _ { 9 } \left( x ^ { 2 } - 8 x \right) = 1$

A) $\{ 9 , - 1 \}$
B) $\{ - 9,1 \}$
C) $\{ 9 \}$
D) $\{ 1 \}$