Solve by Completing the Square $a ^ { 2 } + 2 a - 48 = 0$

Solve by completing the square.
- $a ^ { 2 } + 2 a - 48 = 0$

A) a = -6, 8
B) a = 6, -8
C) a = -40, -8
D) $a = \pm \sqrt { - 48 }$