Find the Domain of the Rational Function $$f ( x ) = \frac { x ^ { 2 } - 81 } { x ^ { 2 } + 7 x - 18 }$$

Multiple Choice

Find the domain of the rational function.
- $$f ( x ) = \frac { x ^ { 2 } - 81 } { x ^ { 2 } + 7 x - 18 }$$

A) domain of $f : ( \infty , - 9 ) \cup ( - 9,9 ) \cup ( 9 , \infty )$
B) domain of $f : ( \infty , - 9 ) \cup ( - 9,2 ) \cup ( 2 , \infty )$
C) domain of $f : ( \infty , - 2 ) \cup ( - 2,9 ) \cup ( 9 , \infty )$
D) domain of $f : ( \infty , 0 ) \cup ( 0 , \infty )$