Please help answer these questions with an explanations and shown work, please use a graph so I can learn from this please!!

5. A grandmother invested $15,000 in 2010 for her newborn granddaughter's college fund. She forgot the annual interest rate, but noticed that the value had appreciated to $23,000 by the year 2023. a. Determine the 1-year change factor b. Define variables and write an exponential function that models the scenario. c. Determine how much the investment will be valued when her granddaughter turns 18 in 2028. 6. A scientist begins with 150 mg of a radioactive substance that has a half-life of 4 days. a. Determine the 1-day change factor b. Define variables and write an exponential function that models the scenario. c. How much of the sample will remain after one week