By definition, a Perfect square is a number that is the square of an Integer.
In this case, you have the following expression given in the exercise:

You can identify that:

Therefore, it is a Perfect square.
Notice that:

Therefore, it is a Perfect square.
For this case you must apply the Difference of two squares is:

Then, you can factor the expression:

The answers are:
- Factored expression:

- ´Perfect squares:
