9-3 Solving Quadratic Equations

Objective

To solve quadratic equations by graphing and using square roots

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The situation in the Solve It can be modeled by a quadratic equation.

Essential Understanding Quadratic equations can be solved by a variety of methods, including graphing and finding square roots.

One way to solve a quadratic equation a x 2 + b x + c = 0 eh x squared , plus b x plus c equals 0  is to graph the related quadratic function y = a x 2 + b x + c . y equals , eh x squared , plus b x plus c .  The solutions of the equation are the x-intercepts of the related function.

A quadratic equation can have two, one, or no real-number solutions. In a future course you will learn about solutions of quadratic equations that are not real numbers. In this course, solutions refers to real-number solutions.

The solutions of a quadratic equation and the x-intercepts of the graph of the related function are often called roots of the equation or zeros of the function.

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