Question

For what values of x is the rational expression below undefined?x-7/x^2-7x-8

Answer 1

the zeros/roots of the denominator will make the rational expression be undefined :)

Answer 2

Any value of \(x\) that makes the denominator (\(x^2-7x-8\)) equal to 0 is a restricted value because dividing by 0 doesn't have a meaningful result.

Note that you have to do this determination before you simplify the expression (if it can be simplified), because the restricted values still apply to the simplified expression, even if the terms that cause them have been simplified away.

Answer 3

Do you know how to factor the denominator? That will make spotting the undefined values easier.