Respuesta :
The appropriate choice is ...
D: Function 1 shows a greater rate of change, because Maddy spends $20 each month and Caitlin spends $18 each month.
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Each time the month number in Function 1 goes up by 1, the account balance goes down by $20. Each time the month number in Function 2 goes up by 1, the account balance goes down by $18. Once you have figured out that $20 is more than $18, you know the first two answers cannot be right. The third answer is wrong because Caitlin cannot (and does not) spend -$18 each month.
D: Function 1 shows a greater rate of change, because Maddy spends $20 each month and Caitlin spends $18 each month.
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Each time the month number in Function 1 goes up by 1, the account balance goes down by $20. Each time the month number in Function 2 goes up by 1, the account balance goes down by $18. Once you have figured out that $20 is more than $18, you know the first two answers cannot be right. The third answer is wrong because Caitlin cannot (and does not) spend -$18 each month.