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Khan Academy on a Stick

Algebra

Coordinate plane

How can we communicate exactly where something is in two dimensions? Who was this Descartes character? In this tutorial, we cover the basics of the coordinate plane. We then delve into graphing points and determining whether a point is a solution of an equation. This will be a great tutorial experience if you are just starting to ramp up your understanding of graphing or need some fundamental review.

Graphing solutions to equations

In this tutorial, we'll work through examples that show how a line can be viewed as all of coordinates whose x and y values satisfy a linear equation. Likewise, a linear equation can be viewed as describing a relationship between the x and y values on a line.

Linear and nonlinear functions

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!

x-intercepts and y-intercepts of linear functions

There are many ways to graph a line and this tutorial covers one of the simpler ones. Since you only need two points for a line, let's find what value an equation takes on when x = 0 (essentially the y-intercept) and what value it takes on when y = 0 (the x-intercept). Then we can graph the line by going through those two points.

Proportional relationships and rates of change

In this tutorial we'll think deeper about how one variable changes with respect to another. Pay attention because you'll find that these ideas will keep popping up in your life!

Slope

If you've ever struggled to tell someone just how steep something is, you'll find the answer here. In this tutorial, we cover the idea of the slope of a line. We also think about how slope relates to the equation of a line and how you can determine the slope or y-intercept given some clues. This tutorial is appropriate for someone who understands the basics of graphing equations and want to dig a bit deeper. After this tutorial, you will be prepared to start thinking deeper about the equation of a line.

Graphing linear equations in slope-intercept form

Math is beautiful because there are so many way to appreciate the same relationship. In this tutorial, we'll use our knowledge of slope to actually graph lines that have been expressed in slope-intercept form.

Analyzing linear functions

Linear functions show up throughout life (even though you might not realize it). This tutorial will have you thinking much deeper about what a linear function means and various ways to interpret one. Like always, pause the video and try the problem before Sal does. Then test your understanding by practicing the problems at the end of the tutorial.

Constructing equations in slope-intercept form

You know a bit about slope and intercepts. Now we will develop that know-how even further to construct the equation of a line in slope-intercept form.

Point-slope form and standard form

You know the slope of a line and you know that it contains a certain point. Well, in this tutorial, you'll see that you can quickly take this information (and that knowledge the definition of what slope is) to construct the equation of this line in point-slope form! You'll also manipulate between point-slope, slope-intercept and standard form.

More analytic geometry

You're familiar with graphing lines, slope and y-intercepts. Now we are going to go further into analytic geometry by thinking about distances between points, midpoints, parallel lines and perpendicular ones. Enjoy!

Graphing linear inequalities

In this tutorial we'll see how to graph linear inequalities on the coordinate plane. We'll also learn how to determine if a particular point is a solution of an inequality.

Triangle similarity and constant slope

Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane. We'll connect this idea to the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b (cc.8.ee.6).