On a coordinate plane, 4 points are plotted. The points are (1, 48), (2, 12), (3, 3), (4, 1).
 Determine the explicit formula for the geometric sequence represented by the graph. 
 f(x) = (one-fourth) Superscript x
 f(x) = 48 (one-fourth) Superscript x minus 1
 f(x) = (4)x
 f(x) = 48(4)x – 1