Functions
Functions is a foundational Grade 8 algebra skill that introduces students to the concept of a function as a relationship where each input has exactly one output. Students learn function notation, identify functions from tables, graphs, and mapping diagrams, and distinguish functions from non-functions.
Key Concepts
New Concept A function is a rule that connects inputs to outputs. For every single input, there is exactly one unique output—no exceptions! What’s next Next, you’ll explore how to represent functions using tables and graphs. We will see how to spot the difference between linear and proportional relationships.
Common Questions
What is a function in math?
A function is a relationship between inputs and outputs where each input (x-value) is paired with exactly one output (y-value).
How do you determine if a relation is a function?
Check that no x-value is repeated with a different y-value. On a graph, use the vertical line test: a relation is a function if any vertical line crosses the graph at most once.
What is function notation?
Function notation is written as f(x), read as f of x, where x is the input and f(x) is the output.
What is the vertical line test?
The vertical line test says a graph represents a function if every vertical line crosses the graph at most once.
What grade covers functions?
Functions are introduced in Grade 8 math and developed further in high school algebra.