A hexagon is a polygon with 6 sides. Furthermore, since it is a regular polygon, we know that all the sides and angles are equal.
So we can factor out a 6 from the given expression to write the perimeter as:
6(2c - 3)
This expression would be like expression 2 from the example at the top of your picture.
We can also express the perimeter like the first example:
(2c - 3) + (2c - 3) + (2c - 3) + (2c - 3) + (2c - 3) + (2c - 3)
Adding 6 copies of (2c - 3) together is the same thing as multiplying by 6.
The length of ONE side is 2c - 3 because all the sides are the same. Therefore we can divide the perimeter by the number of sides:
