Lesson Summary

If you did the operations correctly, you may have a table like this:

As you can observe, the second differences, which are the differences of the first differences, are constant in quadratics:

• The second differences will always be a constant number.
• If the second differences of a table of values do not form a constant number, it indicates that the relation is not quadratic.

The consistency of the second differences being constant is a key property to remember about quadratic functions.