Find All Real Values of X Such That F(x) = $f ( x ) = \frac { 81 - x ^ { 2 } } { 3 }$

Multiple Choice

Find all real values of x such that f(x) = 0.
$f ( x ) = \frac { 81 - x ^ { 2 } } { 3 }$

A) x = ±12
B) x = ±13
C) x = ±11
D) x = ±10
E) x = ±9