Quadratic Equations

Click Here to go to the page on how to graph quadratic equations like y = ax^2+bx+c, which are parabolas.

There are several techniques for solving Quadratic Equations:

1) Factoring; 2) Square Root Property; 3) Completing the Square; 4) Quadratic Formula

I also list videos (see bottom) that show how to solve equations that are Quadratic in Form, or are radical equations or rational equations that become quadratic equations.

See below for videos on each method.

Go to the following link to see how to solve quadratic equations by factoring. This technique only works if the equation can be factored.

Solving Quadratic (and other non-linear Equations) by factoring

QE1: Solving Equations by Factoring 1: http://youtu.be/hadbOzKIdys

QE2: Solving Equations by Factoring 2: http://youtu.be/uvqFKHU-fjg

Watch this sequence of videos in order to understand and learn more methods you can use to solve quadratic equations, including using the square root property, completing the square, and the quadratic equation.

Below are videos showing how  to solve quadratic equations using the Square Root Property of Equations.  The videos have several examples.

QE3: Square Root Property of Equations 1

http://youtu.be/6QTNwvnIoDk

QE4: Square Root Property of Equations 2

http://youtu.be/lpscRx-Mfdk

QE5: Square Root Property of Equations 3

http://youtu.be/CTdk7UR9L54

Below are videos showing how to solve quadratic equations by Completing the Square using Square Root Property of Equations.  The videos have several examples.

QE6: Completing the Square 1

http://youtu.be/aOS6OfB5-9o

QE7: Completing the Square 2

http://youtu.be/jP43EY-S_tg

QE8: Completing the Square 3

http://youtu.be/Ur3mFyTKqQg

QE9: Completing the Square 4

http://youtu.be/lgWa6CvJjYw

QE10: Completing the Square 5

http://youtu.be/kx8t-jR_3ZY

See also: *Completing the Square and Quadratic Formula 2 (below next video)

QE11: Completing the Square and Deriving the Quadratic Formula 1

In this video, we complete the square on a general quadratic equation in standard form to derive the quadratic formula, and learn a song sung to Pop goes the Weasel to help remember the Quadratic Formula.

http://youtu.be/SCfHulybCH8

QE12: *Completing the Square and Quadratic Formula 2

An example done both ways where coefficient of x-squared is 3

http://youtu.be/O4ndRAX5hmc

QE13: The Discriminant: This video defines the discriminant and shows how it is used to determine the kinds of solutions a quadratic equation has, without solving for the actual solutions.

http://youtu.be/QOqA8KQMJhE

Below are videos showing how to solve quadratic equations using the Quadratic Formula.  

The videos have several examples.

QE14: Quadratic Formula 1

http://youtu.be/LkmjnxZ-FuU

QE15: Quadratic Formula 2

http://youtu.be/uhHWlBLpvWA

QE16: Quadratic Formula 3

http://youtu.be/mC3UptAwj8U

QE17: Quadratic Formula 4

http://youtu.be/p1o3I9nALGY

QE18: Quadratic Formula 5

http://youtu.be/2RybRJ3aKJY

Below is the first video I made on the Quadratic Formula.  It begins with the song, and then shows how to derive the Quadratic formula, and shows how to solve a problem using the quadratic formula.  This has basically the same info as video QE11.

Quadratic Formula Song, How to derive the Quadratic Formula by completing the square, and one example using the quadratic formula

http://youtu.be/uK_RWZ1L9tE

QE19: Writing Quadratic Equation from Solutions 1:

http://youtu.be/KIaTOkdQMhI 

QE20: Writing Quadratic Equation from Solutions 2: 

http://youtu.be/O1tHVKvyH3o

QE21: Writing Quadratic Equation from Solutions 3: 

http://youtu.be/_ARmnz-qd1c

QE22: Writing Quadratic Equation from Solutions 4: 

http://youtu.be/qvZA7KCbWkU

QE23: Writing Quadratic Equation from Solutions 5: 

http://youtu.be/M50LCcFrGCc

Videos showing how to solve equations that are Quadratic in Form, or how to solve rational or radical equations that become quadratic equations.

QE24: Solving a Radical Equation that becomes a Quadratic Equation 1

http://youtu.be/edLm17B5pnU

QE25: Solving a Rational Equation that becomes a Quadratic Equation 1

http://youtu.be/Z50kmCwgivs

QE26: Solving a Rational Equation that becomes a Quadratic Equation 2

http://youtu.be/dGM7obRrJqs

QE27Solving an Equation that is Quadratic in Form 1

http://youtu.be/9VDI66n13hk

QE28: Solving an Equation that is Quadratic in Form 2

http://youtu.be/2N0tgulqC3s

QE29: Solving an Equation that is Quadratic in Form 3

http://youtu.be/skrJkhIm78Q

QE30: Solving an Equation that is Quadratic in Form 4

http://youtu.be/RRLgMycB6Xg

Max and Min Problems--uses the idea of the vertex of a parabola to find a minimum or maximum value