Given f(x) = [(x^2 -2x -15)/x-5], notice it is a rational
function
But the numerator x^2 -2x -15 could be factored, which
yields
(x – 5)(x + 3)
Therefore f(x) = (x – 5)(x + 3)/ (x-5)
Cancelling x-5, f(x)
= x + 3
In this way, the f(x) is continuous at any point, and is
basically a line.
