The perimeter of a square is 80 minus 64 y units. Which expression can be used to show the side length of one side of the square? 16 (5 minus 4 y): Each side measures 5 minus 4 y units. 16 y (5 minus 4): Each side measures 5 minus 4 units. 4 (20 minus 16 y): Each side measures 20 minus 16 y units. 4 y (20 minus 16): Each side measures 20 minus 16 units.