Functions - Overview

The Functions domain focuses on understanding relationships between variables, interpreting graphs, and analyzing mathematical models.

Function concepts appear frequently on the ACT and connect algebra, graphing, and real-world applications.

What You’ll Learn

By working through this domain, you’ll learn how to:

Understand function notation
Evaluate functions
Analyze graphs
Determine domain and range
Work with transformations
Compose functions
Find inverse functions
Interpret function behavior in context

Course Structure

Topics in this domain include:

Function notation
Evaluating functions
Graphing functions
Domain and range
Transformations
Composition
Inverse functions
Linear functions
Quadratic functions
Exponential functions

ACT Functions Tips

Pay attention to input and output values.
Learn common graph shapes.
Understand transformations visually.
Connect equations with graphs.
Check domain restrictions carefully.

Assess Your Progress

After completing the lessons, reinforce your understanding through:

Lesson practice questions
Unit assessments
ACT Domain Tests
Full-Length ACT Practice Tests

Select a topic from the sidebar to begin.