Find the Vertex of the Graph of the Quadratic Function $$f ( x ) = x ^ { 2 } + 14 x - 9$$

Multiple Choice

Find the vertex of the graph of the quadratic function.
- $$f ( x ) = x ^ { 2 } + 14 x - 9$$

A) $( 7,138 )$
B) $( 14,383 )$
C) $( - 7 , - 156 )$
D) $( - 7 , - 58 )$