Ok so east is the right side. The length of the east side would be (2x) + (2x+4). You can then simplify this to 4x + 4 but I don't know if your teacher wants you to do that. Hope this helps!
I show you how to do it in the picture below. To find each side you just add the two equations together. And to find the perimeter you take the sum of each side and add them together.
