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Algebra 2 Review 8.1-8.3 Name __________________________________ Lesson 8.1 Without graphing, determine whether each equation represents exponential growth or exponential decay. 9 x 1. y = 10x 2. y = 0.5(1.67)x 3. y = 1.023(0.98)x 4. y = 2( 10 ) Write an exponential equation y = abx whose graph passes through the given points. 5. (1, 10), (2, 25) 6. (2, 128), (-1, 16) 7. (-2, 0.05), (2, 12.8) What percent of increase or decrease does the function model? 8. y = 15(1.45)x 9. y = 0.32(.99)x 10. y = 0.1(1.7)x 11. y = 7.3(0.8)x 12. Mr. Anderson put $1000 into an account that earns 4.5% annual interest. The interest is compounded continuously and there are no withdrawals. How much money will be in the account at the end of 30 years? 13. A manufacturer bought a new rolling press for $48,000. It has depreciated in value at an annual rate of 15%. What is the value 5 years after purchase? Lesson 8.2 Graph each function. 14. y = 3x 15. y = 2(4)x 16. y = -1(2)x+2 + 3 Evaluate each expression to four decimal places. 17. e3 18. e1/4 19. e 5 20. e-1 21. You place $900 in an investment account that earns 6% interest compounded continuously. Find the balance after 5 years. 22. I-123 is used in thyroid scans. It has a half-life of 13.2 hours. Write the exponential decay function for a 45-mg sample. Find the amount remaining after 5 hours. Lesson 8.3 Write each equation in exponential form. 23. log4256 = 4 24. log8 1 = -2 64 25. log17289 = 2 26. log36561 = 8 Write each equation in logarithmic form. 27. 92 = 81 28. 10-3 = 0.001 29. 29 = 512 30. 6-3 = Evaluate each logarithm. 31. log216 32. log5125 33. log432 34. State the parent function. Then explain the translation. 35. y = log3(x + 1) 36. y = log2x – 3 37. y = log4(x – 4) + 1 1 216 log1212