Solve the Problem $f ( x ) = x ^ { 2 } + 2 x - 60$

Multiple Choice

Solve the problem.
-Given $f ( x ) = x ^ { 2 } + 2 x - 60$ find all values for $x$ for which $f ( x ) \leq - 12$ .

A) $[ - 8,6 ]$
B) $( - 8,6 )$
C) $\varnothing$
D) $( - \infty , - 8 ] \cup [ 6 , \infty )$