SOLUTION: Find all numbers for which the rational expression is undefined. r^3-8r r^2-16 (Use comma to separate answers.) I have no idea what I am doing here, please help Tjj

Algebra ->  Rational-functions -> SOLUTION: Find all numbers for which the rational expression is undefined. r^3-8r r^2-16 (Use comma to separate answers.) I have no idea what I am doing here, please help Tjj       Log On


   

Question 177675: Find all numbers for which the rational expression is undefined.
r^3-8r
r^2-16
(Use comma to separate answers.)
I have no idea what I am doing here, please help
Tjj
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


I presume you mean .

If this is the case, then the entire rational function would be undefined for any value of the variable that makes the denominator expression equal to zero.

So solve:

,

which rather conventiently factors:

,

Which means that



or



Hence, the original rational expression is undefined for 4, -4