## Subscribe $4.99/month Un-lock Verified Step-by-Step Experts Answers. ## Textbooks & Solution Manuals Find the Source, Textbook, Solution Manual that you are looking for in 1 click. ## Tip our Team Our Website is free to use. To help us grow, you can support our team with a Small Tip. ## Holooly Tables All the data tables that you may search for. ## Holooly Help Desk Need Help? We got you covered. ## Holooly Arabia For Arabic Users, find a teacher/tutor in your City or country in the Middle East. Products ## Textbooks & Solution Manuals Find the Source, Textbook, Solution Manual that you are looking for in 1 click. ## Holooly Arabia For Arabic Users, find a teacher/tutor in your City or country in the Middle East. ## Holooly Help Desk Need Help? We got you covered. ## Chapter 3.1 ## Q. 3.1.1 ## Q. 3.1.1 Evaluating an Exponential Function The exponential function $f(x)=42.2(1.56)^x$ models the average amount spent, f(x), in dollars, at a shopping mall after x hours. What is the average amount spent, to the nearest dollar, after four hours? ## Step-by-Step ## Verified Solution Because we are interested in the amount spent after four hours, substitute 4 for x and evaluate the function. $f(x)=42.2(1.56)^x$ This is the given function. $f(4)=42.2(1.56)^4$ Substitute 4 for x. Use a scientific or graphing calculator to evaluate f(4). Press the following keys on your calculator to do this: Scientific calculator: $42.2 \fbox{×} 1.56 y^{x} 44 \fbox{=}$ Graphing calculator: $42.2 \fbox{×} 1.56 \fbox{∧} 4 \fbox{ENTER}.$ The display should be approximately 249.92566. $f(4)=42.2(1.56)^4 \approx 249.92566 \approx 250$ Thus, the average amount spent after four hours at a mall is$250. 