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Ch. 2 - Graphs and Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 3, Problem 16

Determine whether each relation defines a function. {(-12,5),(-10,3),(8,3)}

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1
Recall that a relation defines a function if every input (x-value) corresponds to exactly one output (y-value).
List the input values from the given relation: -12, -10, and 8.
Check if any input value is repeated with a different output value. Here, -12, -10, and 8 each appear only once.
Since no input value is repeated with different outputs, each input has exactly one output.
Conclude that the given relation does define a function because each input maps to a unique output.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Definition of a Relation

A relation is a set of ordered pairs, where each pair consists of an input (x-value) and an output (y-value). It shows how elements from one set correspond to elements in another set. Understanding relations is fundamental to analyzing whether they meet the criteria of a function.
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Definition of a Function

A function is a special type of relation where each input (x-value) is paired with exactly one output (y-value). This means no x-value can appear more than once with different y-values. Recognizing this helps determine if a given relation qualifies as a function.
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Testing a Relation for Functionality

To test if a relation is a function, check if any x-values repeat with different y-values. If all x-values are unique or repeated with the same y-value, the relation is a function. This method is essential for evaluating sets of ordered pairs like the one given.
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