Chapter 5 Performance Task Describing Change How can you use algebraic expressions to predict change over time in different real-life situations? Change is everywhere. A teen measures the growth of the balance in a savings account. A park ranger observes changes in temperature. A parent records the growth of a child. A scientist measures the growth of two plants. Answer the following questions for cach data set. a. What is the first recorded value in the data set? b. How much does the recorded value change each time period? Does the recorded value change by approximately the same amount cach period? c. Write an expression of the form ax + b to model the data set, or explain why this type of expression is not appropriate. d. Use your expression to predict the next value, if possible. 1. Your sister is enjoying her first job-especially the paychecks! She opens a savings account and deposits part of her paycheck each week. Date Transaction Deposit Withdrawal Interest Balance Starting balance $0.00 6/2 Deposit #1 $25.00 $25.00 Deposit #2 $25.00 $50.00 6/16 Deposit #3 $25.00 $ 75.00 6/23 Deposit #4 $ 25.00 $100.00 6/30 Deposit #5 $25.00 $125.00 2. Winter is coming, and the park ranger enjoys watching the changing of the seasons. Each morning, the park ranger records the outside temperature and plots it in a graph to watch how it is changing. Daily Park Temperature at 8:00 A.M. Temperature ('F) 54 52 50 48 47 45 sept. 15 opt. 17 Sept. 18 Sept. 19 Sept. 20 Sept. Sept. Date recorded Copyright @ Big Ideas Learning, LLC Big Ideas Math: Modeling Real Life Grade 6 All rights reserved. Assessment Book Chapter 5 Performance Task (continued) Describing Change 3. Your cousin is starting first grade this year. His parents have been tracking his growth since he was a toddler. They record his height on his birthday each year on a growth chart. 6 yr. old - 49 in. 5 yr. old - 46 in. 4 yr. old - 44 in. 3 yr. old - 40 in. 2 yr. old - 35 in. 1 yr. old - 27 in. 4. A botanist, a scientist who studies plants, is conducting an experiment about the effects of different kinds of lighting on the growth of a plant. She starts with two plants of equal size and measures them regularly to compare their growth. The table below shows the data she has recorded in her journal. Plant A Plant B Day O 2" 2" Day 15 2.4" 2.5' Day 30 2.6" 2.9" Day 45 2.5" 3.4" Day 60 2.3" 3.8" Day 75 2.2" 4.3"