Find $g \circ f$ ​ $f ( x ) = x - 9 \quad g ( x ) = x ^ { 2 }$

Multiple Choice

Find $g \circ f$ .​ $f ( x ) = x - 9 \quad g ( x ) = x ^ { 2 }$ ​

A) $( g \circ f ) ( x ) = x ^ { 2 } - 18 x + 81$
B) $( g \circ f ) ( x ) = x ^ { 2 } - 81$
C) $( g \circ f ) ( x ) = x ^ { 2 } - 9 x + 81$ ​
D) $( g \circ f ) ( x ) = x ^ { 2 } - 9$
E) $( g \circ f ) ( x ) = x ^ { 2 } + 81$