Question 884798
You cannot divide by zero. You cannot do something like 1/0. This is undefined.


So that means the denominator x - 8 cannot be zero.


IF the denominator was zero, then 


x-8 = 0


x = 8


So IF the denominator was zero, then x = 8. Go backwards and that means x = 8 causes the denominator to be zero.


So x = <font size=5 color="red">8</font> makes the expression undefined.