What is the product of the two integer values of x for which |x^2- 16| is a prime number?
If x = 3 then | (3)2 - 16 | = | 9 - 16 | = | -7 | = 7
If x = -3 then | (-3)2 - 16 | = | 9 - 16 | = | -7 | = 7
-3 x 3 = ...
