How can you tell whether a function is rational or not? And how do you determine holes of a graph? Thanks!

Answer 1

A hole in a graph is when the denominator can be zero. If f(x)=x/(x-3) then x=3 will be a hole, as the denominator has a zero there.

http://id.mind.net/~zona/mmts/functionInstitute/rationalFunctions/definition/definition.html