# 1.2 Functions and Graphs

Determine whether a correspondence or a relation is a function.

Find function values, or outputs, using a formula or a graph.

Graph functions.

Determine whether a graph is that of a function.

Find the domain and the range of a function.

Solve applied problems using functions.

We now focus our attention on a concept that is fundamental to many areas of mathematics—the idea of a *function*.

# Functions

Used-Book Co-op. A community center operates a used-book co-op, and the proceeds are donated to summer youth programs. The total cost of a purchase is $2.50 per book plus a flat-rate surcharge of $3. If a customer selects 6 books, the total cost of the purchase is

We can express this relationship with ...

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