Write an exponential function for each set of points.
a. (0,3), (1, 12), (2, 48), (3, 192), and (4, 768)

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.