AIM: How can we determine if a linear relationship is increasing or decreasing?
Announcements: Midterms are Wednesday and Thursday, January 18 & 19
HW: Unit 3 Textbook p.20 #12
A woman opens a bank account with $40 and then depositis $20 each week. How can you determine if the relationship between money in the account and number of weeks is linear? Explain. If it is linear, will the line be increasing or decreasing?
Ans: The relationship is linear because there is a constant rate of change, in this case, $20 per week. Since the money is being deposited, the amount of money is increasing, because when money is put into a bank, the account increased. The relationships is NOT proportional since there was a starting value of $40, which means the line could not pass through the origin.
Classwork: We applied our knowledge of linear relationships to look at relationships with negative rates of change. We used the example of having $144 in a bank account and withdrawing $12 each week. Students sketched graphs, assigned variables, and wrote equations to model the situation.