Let us look once again at the graph we examined in the previous tutorial:
Continuous Functions
The function f(x) is continuous at x = a if
The function f is said to be continuous on its domain if it is continuous at each point in its domain. If f is not continuous at a particular point a, we say that f is discontinuous at a or that f has a discontinuity at a. Example

Back in the tutorial on functions from the graphical viewpoint, we looked at the following function:
f(x)  = 

Now look at the following graphs. None of the functions shown is defined at x = 10. However, two of them can be made continuous by defining f(10) = 15. Click on those two graphs.
You will see more about continuous functions in the next tutorial when we discuss them algebraically.
Now try the rest of the exercises in Section 3.2 in Applied Calculus or Section 10.2 in Finite Mathematics and Applied Calculus
Alternatively, go on to the algebraic approach.