Examples, solutions, and videos to help Algebra I students learn how to derive the quadratic formula by completing the square for a general quadratic equation in standard form, ax2 + bx + c = 0 , and use it to verify the solutions for equations from the previous lesson for which they have already factored or completed the square.
Lesson 14 Summary
The quadratic formula is derived by completing the square on the general form of a quadratic equation ax2 + bx + c = 0, where a ≠ 0. The formula can be used to solve any quadratic equation and is especially useful for those that are not easily solved by using any other method (i.e., by factoring or completing the square).
The following diagram shows how to derive the Quadratic Formula. Scroll down the page for more examples and solutions on how to use the quadratic formula to solve equations.
Lesson 14 Problem Set Sample Solutions
Use the quadratic formula to solve each equation.
Try the free Mathway calculator and
problem solver below to practice various math topics. Try the given examples, or type in your own
problem and check your answer with the step-by-step explanations.
We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page.