Question 144982
This expression is defined for all x except where that value of x makes the denominator 0.

So factor the denominator
{{{X^2+4X-5}}}
{{{(x+5)(x-1)}}}

When x equal 1 or x equal -5, the denominator is 0. Anything divided by 0 is undefined.
 
All values except 1 and -5