Mark opens a savings account with an initial deposit of $2000. He deposits $35 each week. Elizabeth's savings account is represented by the function y = $45x + $2800, where y is the balance of Elizabeth's savings account after her initial deposit and a number of weekly deposits, x. Which statement BEST compares the rate of change for the two accounts?
answer choices:
Elizabeth deposited $800 less than mark
Mark deposits $10 more each week than Elizabeth.
Elizabeth deposits $7 for every $9 Mark deposits
Mark deposits $10 less each week than Elizabeth
+23246 y = ax + b ---> the slope (a) represents the weekly deposit
the intercept (b) represents the initial deposit
Mark: initial deposit = $2000 weekly deposit = $35 his equation: y = 35x + 2000
Elizabeth: initial deposit = $2800 weekly deposit = $45 her equation: y = 45x + 2800
Elizabeth deposited $800 more than Mark.
Mark deposits $10 less each week than Elizabeth
Elizabeth deposits $45 for every $35 that Mark deposits; as a fraction, this is $45/$35 = 9/7, not 7/9
