Virtual Nerd: What's the Direct Variation or Direct Proportionality Formula?

This video solves a basic direct variation problem: the cost of buying gas for your car varies directly with the number of gallons you need to purchase. Sal shows how to write a direct variation equation based on this problem and solves...

It's the video your algebra class has been waiting for - Sal explains the quadratic formula! He describes it as "one of at least the top five most useful formulas in mathematics" and recommends that it be memorized, provided one also...

Watch how easy solving proportions can be. Using the means-extremes property of proportions you'll be able to solve a variety of proportion problems. Example problems are worked to show you how this property looks in action. Hint:...

Watch how exponents add when you multiply the same number raised to different exponents. Reviewing the product of powers rule will help you on the SAT! [4:30]

Watch this tutorial to learn about the means-extremes property of proportions that allows you to cross multiply, taking the product of the means and setting them equal to the product of the extremes. [5:59]

Do you remember what order to follow when you simplify an expression? To review for the SAT, watch this tutorial for a reminder of the order of operations. [3:18]

Review your understanding of the power of a product rule before the SAT. This video will give you an explanation along with examples. [4:40]

Review the power of the quotient rule to prep for the SAT. Watch this video and learn how to split an exponent and put it in the numerator and denominator of a fraction using the power of the quotient rule. [4:54]

Watch how exponents add when you divide the same number raised to different exponents. Reviewing the quotient of powers rule will help you on the SAT! [5:20]

Enhance pupil understanding of proportions and variable relationships by studying direct and inverse variation. Use the idea of a proportional relationship to teach direct variation. Then use a similar pattern to help individuals...