1.8_quadratic formula and the discriminant.notebook

1

October 10, 2013

Oct 7­2:01 PM

1.8: Solving Quadratic Equations by the quadratic

formula and the discriminant

Oct 7­2:01 PM

THE QUADRATIC FORMULA

• When a quadratic equation is in standard form:

• use to find your solutions/roots/zeros

Oct 7­2:01 PM

WHY USE THE QUADRATIC FORMULA?

The quadratic formula allows you to solve ANY quadratic equation, even if you cannot factor it.

An important piece of the quadratic formula is what‛s under the radical: b2 – 4ac

This piece is called the discriminant.

        

Oct 7­2:01 PM

WHY IS THE DISCRIMINANT IMPORTANT?

The discriminant tells you the number and types of solutions (roots) you will get.

The discriminant can be +, –, or 0

If the discriminant is positive, there will be two real solutions

If the discriminant is negative, there will be i's in your answer

If the discriminant is 0, then there is one real solution

If the

        

Oct 7­2:06 PM

Review:

Oct 7­2:01 PM

Example #1Find the value of the discriminant and describe the nature of the roots (real,imaginary, rational, irrational) of each quadratic equation. Then solve the equation using the quadratic formula

1.8_quadratic formula and the discriminant.notebook

2

October 10, 2013

Oct 9­1:41 PM Oct 9­10:45 AM

Solve the following using the quadratic formula.  Tell what kind of solution the quadtratic has (rational, irrational, imaginary)

Oct 9­10:44 AM Oct 9­10:44 AM

Oct 9­10:44 AM Oct 9­10:44 AM