Answer:
To find the values for x so that the perimeter of the rectangle is not greater than 60 cm, includes 25 cm on one side, we have already found the first half of this answer.
The only way to make this < 60 is to have the parallel sides (depending on which side is 25,) is 5 cm. That way, it will be exactly 60 cm, meaning we have reached our goal of < 60 cm.
This is the best I can do at the moment.