Michael J. answered 06/01/15
Effective High School STEM Tutor & CUNY Math Peer Leader
We factor f(x) and then set the denominator equal to zero.
f(x) = (x + 8)(x - 8) / (x + 8)(x - 6)
The next thing we can do is cancel out terms. But I warn you. If you do cancel out terms such as (x + 8), you limit any solutions that you can have. So we will not cancel out terms.
Set the denominator equal to zero.
(x + 8)(x - 6) = 0
x = -8 and x = 6
so for the function f(x),
x ≠ -8 and x ≠ 6