What is the discontinuity of the function #f(x) = (x^2-3x-28)/(x+4)# ?
If a rational expression (basically a fraction with a polynomial in the numerator and another polynomial in the denominator) has a discontinuity, it will be where the denominator equals zero.
Now there are two types of discontinuity possible here.
The discontinuity is removable. The graph would look like the line
Note that most graphers will not properly show a hole (as in this case); this is known as a graphing error.