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Doing self-study, but don't know which algebra topics to study or in what order? Purplemath's free math lessons are listed here in study order.

Pre-algebra and algebra lessons, from negative numbers through pre-calculus. Grouped by level of study. Lessons are practical in nature informal in tone, and contain many worked examples and …

Purplemath (PM) kinda happened by accident. Read here about PM's author, Elizabeth Stapel, and about Purplemath, including the origin of its name.

Purplemath What is a linear equation? "Linear" equations are equations containing just a plain old variable like " x ", rather than something more complicated like x2, or x/y, or square roots, or other …

Basic trig identities are formulas for angle sums, differences, products, and quotients; and they let you find exact values for trig expressions.

To access the Purplemath lessons and tutoring forums, please use the links to the right. For paid in-home tutoring, please try here. algebra.help: This site has lessons on basic algebra topics and …

Purplemath When would I use the Quadratic Formula? You can use the Quadratic Formula any time you're trying to solve a quadratic equation — as long as that equation is in the form " (a quadratic …

Purplemath What are exponential functions? Exponential functions look somewhat similar to functions you have seen before, in that they involve exponents, but there is a big difference, in that the variable …