Question 281864
{{{[s^3-8s]/[s^2-64]}}}
{{{[s(s^2-8)]/[(s+8)(s-8)]}}}
.
It is undefined if the denominator is zero.
It is zero if
(s+8)=0
or
(s-8)=0
.
Therefore, it is undefined if 
s = {-8, 8}