Solve the Problem $f ( x ) = x ^ { 2 } + 15 x$

Multiple Choice

Solve the problem.
-Let $f ( x ) = x ^ { 2 } + 15 x$ . Find all values $x$ for which $f ( x ) = - 54$ .

A) $0 , - 54$
B) 9,6
C) $- \frac { 5 } { 18 } , - \frac { 1 } { 54 }$
D) $- 9 , - 6$