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2.1 Solving Quadratic Equations February 21, 2013 Unit 2 Quadratic Equations

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Page 1: 2.1 Solving Quadratic Equations by Graphing

2.1 Solving Quadratic Equations February 21, 2013

Unit 2Quadratic Equations

Page 2: 2.1 Solving Quadratic Equations by Graphing

2.1 Solving Quadratic Equations February 21, 2013

In this chapter, we will look at quadratic equations that follow the formula ax2 + bx + c = 0.  You will be asked to solve the quadratic equation.

When we want to solve a quadratic equation, we are looking for the roots of the equations.

We are essentially solving for x.

There are several ways to solve a quadratic equation:

1. Graphing2. Factoring3. Completing the Square4. Using the Quadratic Equation

Page 3: 2.1 Solving Quadratic Equations by Graphing

2.1 Solving Quadratic Equations February 21, 2013

Solving Quadratic Equations by Graphing

When we solve a quadratic equation by graphing, we will find the x­intercepts.  These are called the roots.  

How many roots?

The number of roots varies. There are there possibilities:

Page 4: 2.1 Solving Quadratic Equations by Graphing

2.1 Solving Quadratic Equations February 21, 2013

E.G. The manager of Jasmine's Fine Fashions is investigating the effect that raising or lowering dress prices has on the daily revenue from dress sales. The function R(x) = 100 + 15x ­ x2 gives the store's revenue R, in dollars, from dress sales, where x is the price change, in dollars. What price changes will result in no revenue?

Page 5: 2.1 Solving Quadratic Equations by Graphing

2.1 Solving Quadratic Equations February 21, 2013

E.g. 2. Solve 2x2 + x = ­2 by graphing

pg 215#1, 2, 3ef