# Algebra I

Algebra is the language through which we describe patterns. Think of it as a shorthand, of sorts. As opposed to having to do something over and over again, algebra gives you a simple way to express that repetitive process. It's also seen as a "gatekeeper" subject. Once you achieve an understanding of algebra, the higher-level math subjects become accessible to you. Without it, it's impossible to move forward. It's used by people with lots of different jobs, like carpentry, engineering, and fashion design. In these tutorials, we'll cover a lot of ground. Some of the topics include linear equations, linear inequalities, linear functions, systems of equations, factoring expressions, quadratic expressions, exponents, functions, and ratios.
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# Ratios and proportions

What ratios and proportions are. Using them to solve problems in the real world.
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All content in “Ratios and proportions”

## Ratios and proportions

You remember a thing or two about ratios and proportions from your pre-algebra days. Well, how can we use these same ideas to solve problems in algebra? This tutorial re-introduces ratios in an algebraic context and helps us solve some awesome problems!

## Advanced ratios, proportions, and rates

In this tutorial, we will explore more advanced examples involving ratios, proportions, and rates.

## Direct and inverse variation

Whether you are talking about how force relates to acceleration or how the cost of movie tickets relates to the number of people going, it is not uncommon in this universe for things to vary directly. Similarly, when you are, say, talking about how hunger might relate to seeing roadkill, things can vary inversely. This tutorial digs deeper into these ideas with a bunch of examples of direct and inverse variation.

## Rational and irrational numbers

In this tutorial, we'll use the powers of algebra to actually prove what we've always suspected to be true of rational and irrational numbers!