The total cost of an item including sales tax is directly proportional to its price. if the total cost of a $25 item is $25.75, what is the total cost on a $60 item? a)$60.75 b)$618 c)$61.80 d)$103

a function could be identified in 3 ways either on a chart,graph, or ordered pairs. first a function is that each point has its own. the rule is that there can be many x's to one y but there can not be 2 x's at different y's. so on a graph when you put a straight line through the y's there should be one dot only to be a function.

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you need to add a picture