1. Determine whether each function is an example of exponential growth or decay. Then find the y-intercept. a) y = 2(4)x b) y = 3(.25)x growth or decay growth or decay y-intercept: y-intercept: 2. Write a function for the situation described and find the value after 5 yrs. A $12,500 car depreciates 9% each year. 3. Some investments in the stock market have earned 12% annually. At this rate, earnings can be found using the formula A = P(1.12)n, where A is the total value of the investment, P is the initial value of the investment, and n is the number of years the money is invested. If $5000 is invested in the stock market at this annual rate of return, what is the expected total value after 20 years? 4. The pH of a liquid is a measure of how acidic or basic it is. The concentration of hydrogen ions in a liquid islabeled [H+]. Use the formula pH = -log[H+] to find the pH level, to the nearest tenth, of a liquid with [H+] about 7.8 10-12. 5. Describe the transformation done to the parent function y = 2x in each equation below. a) y = 2x + 3 b) y = 2x-4 c) y= 2x+3 - 5 6. Describe the transformation done to the parent function y = log x in each equation below. a) y = log(x + 7) b) y = log x - 6 c) y = log(x - 2) + 3 7. Write each as a single logarithm using the properties of logarithms. a) 3log x - 2log y b) 1 1 log b 15 log b x 2 2 8. Expand each logarithm using the properties of logarithms. a) b) log 7x3y5 log b 3 7 9. Evaluate a) log381 b) log255 c) log 100 d) e4 e) ln(e9) 10.Write this equation as a logarithm. 64 = 1024 5 3 Solve each of the following equations for x showing the algebra you used to do it. Round each answer to the ten-thousandths place. (4 places past the decimal) Then use the graphing calculator to check: Type one side of equation in y 1 and the other in y2 and intersect them. 11. 7x-3 = 25 12. log (3x+1) = 2 13. log(7x+1) = log(x-2) + 1 14. 4e2x - 3 = 12 15. ln 5 + ln x = 3