A chemist has a 100 gram sample of a radioactive material He records the amount of radioactive material every week for 6 weeks and obtains the following data Complete parts a f Week x 0 1 2 3 4 5 6 Weight y in grams 100 0 86 0 72 0 64 1 53 1 45 4 38 8 a Treating week x as the independent variat use a graphing utility to fit an exponential funct to the data y ab Round to four decimal places as needed