# Linear equations and functions

Contents

Linear equations like y = 2x + 7 are called "linear" because they make a straight line when we graph them. These tutorials introduce you to linear relationships, their graphs, and functions.

When you walk at a constant rate, the relationship between the distance you've walked and the time you've spent walking is proportional. In this tutorial, we learn about proportional relationships (constant rates) and their graphs..

Learn how to figure out if an ordered pair is a solution to a linear equation.

Learn about intercepts of a line. Identify intercepts using a table, graph, and equation.

Learn about slope of a line and the slope formula. Identify slope from a graph, two points, and an equation.

Learn about the slope-intercept form of two-variable linear equations, and how to interpret it to find the slope and y-intercept of their line. Find the slope-intercept equation of a line from its graph, a table, or two points.

Learn how to evaluate functions from a formula or graph. Compare linear functions.

Learn to use linear models to show relationships between two variables and represent them using a table, equation, or a graph.

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

Not every relationship in the universe can be represented by a line (in fact, most can't be). We call these "nonlinear". In this tutorial, you'll learn to tell the difference between a linear and nonlinear function!
Have fun!
Common Core Standare: 8.F.A.3