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Relationships can be any association between sets of numbers while functions have only one output for a given input. This tutorial works through a bunch of examples of testing whether something is a valid function. As always, we really encourage you to pause the videos and try the problems before Sal does!
Common Core Standard: 8.F.A.1
Testing if a relationship is a function
Relations and Functions
Sal checks whether a given set of points can represent a function. For the set to represent a function, each domain element must have one corresponding range element at most.
Sal checks whether a table of people and their heights can represent a function that assigns a height to a name.
Sal checks whether y can be described as a function of x if y is always three more than twice x.
Sal explains why a vertical line *doesn't* represent a function.
Determine whether a table of values of a relationship represents a function.
Sal checks whether a description of the price of an order can be represented as a function of the shipping cost.
Determine whether a given graph represents a function.