In 2011, there were 5.18 million YouTube subscribers in the United States. The number of subscribers increased by 179% each year after 2011. Approximately, how many YouTube subscribers were in the United States in 2020? a. Determine if this situation represents exponential growth or decay. Explain your reasoning. b. Write an exponential equation to represent the situation using t for time (in years) and S(t) for the number of YouTube subscribers. c. Identify the growth or decay factor. d. Use your equation from part b to solve the exponential equation the show the numbers of YouTube subscribers in 2020