Solve the Problem $f ( x ) = x ^ { 2 } - 18 x + 68$

Multiple Choice

Solve the problem.
-Given $f ( x ) = x ^ { 2 } - 18 x + 68$ , find all values for $x$ for which $f ( x ) \geq 0$ .

A) $( - \infty , 9 - \sqrt { 13 } ] \cup [ 9 + \sqrt { 13 } , \infty )$
B) $( - \infty , 9 - \sqrt { 13 } ) \cup ( 9 + \sqrt { 13 } , \infty )$
C) $[ 9 - \sqrt { 13 } , 9 + \sqrt { 13 } ]$
D) $( - \infty , - \sqrt { 13 } ] \cup [ \sqrt { 13 } , \infty )$