Answer:
To answer this question, we first need to determine the perimeter of Shawn's garden. If we let x represent the side length of Shawn's garden, then the perimeter of Shawn's garden would be 4x.
Now, the perimeter of Charlie's garden is 12x + 20, which is 8x + 20 larger than the perimeter of Shawn's garden (4x). Therefore, the perimeter of Charlie's garden is 8x + 20 larger than the perimeter of Shawn's garden.