# Interactive video lesson plan for: ❤︎² How to Solve by Completing the Square (mathbff)

#### Activity overview:

MIT grad shows the easiest way to complete the square to solve a quadratic equation. More videos with Nancy coming in 2017! To skip ahead:

1) For quadratic that STARTS WITH X^2, skip to time 1:42.
2) For quadratic that STARTS WITH 2X^2, 3X^2, etc., skip to time 6:46.
3) For NEGATIVE leading term like -X^2, skip to 13:34.
4) If there's NO X TERM (ex. 3x^2 - 121 = 0), then you cannot complete the square and can solve directly - skip to 16:30.

Completing the square means re-arranging the quadratic equation into the neat, "perfect square" form (x + number)^2 equals another number, or (x - number)^2 equals another number. The point of doing this is so that you can solve by just square-rooting both sides of the equation.

If your quadratic equation starts with...

1) just X^2 (for ex: x^2 + 6x - 7 = 0), move constant to right, add (6/2)^2 to both sides, write left side as perfect square, and square root both sides to solve. Remember you get PLUS and MINUS solutions when you square root the constant side.

2) 2X^2 or 3X^2 or 4X^2 etc. (for ex: 2x^2 - 10x - 3 = 0), move constant to right side, DIVIDE EVERY TERM by leading coefficient 2 on left and right side, add (5/2)^2 to both sides, write left side as perfect square and square root both sides to solve.

3) -X^2 or any negative coefficient (for ex: -x^2 - 6x + 7 = 0), move constant to right side, DIVIDE EVERY TERM by -1 on left and right side. (NOTE: if you had -2x^2 in your equation, you would divide every term by -2 on left and right side). Then add (6/2)^2 to both sides, write left side as perfect square and square root both sides to solve.

If you don't have an X term in equation, (for ex: 3x^2 - 121 = 0), then you cannot complete the square. Just move the constant to the right, divide both sides by 3, and square root both sides to solve. Remember plus and minus solutions on the right.

Tagged under: completing square,solving quadratic,quadratic expression,quadratic equation,quadratic formula,quadratic,polynomial,perfect square,square root,factors,factoring,fractions,coefficient,constant,shortcut,trick,rules,explanation,equation,solve,solution,algorithm, find, solve, ,algebra,algebra 2,precalculus,geometry,math,mathematics,khan,jmt,-,easy,find,test,tutor,problem,tips

Clip makes it super easy to turn any public video into a formative assessment activity in your classroom.

Add multiple choice quizzes, questions and browse hundreds of approved, video lesson ideas for Clip

Make YouTube one of your teaching aids - Works perfectly with lesson micro-teaching plans

Play this activity 1. Students enter a simple code 2. You play the video 3. The students comment 4. You review and reflect

* Whiteboard required for teacher-paced activities

## Ready to see what else can do?

With four apps, each designed around existing classroom activities, Spiral gives you the power to do formative assessment with anything you teach.

Quickfire

Carry out a quickfire formative assessment to see what the whole class is thinking

Discuss

Create interactive presentations to spark creativity in class

Team Up

Student teams can create and share collaborative presentations from linked devices

Clip

Turn any public video into a live chat with questions and quizzes

### 1000s of teachers use Spiral to deliver awesome, engaging activities that capture students' understanding during lessons.

Now it's your turn Sign up

### Spiral Reviews by Teachers and Digital Learning Coaches @kklaster

Tried out the canvas response option on @SpiralEducation & it's so awesome! Add text or drawings AND annotate an image! #R10tech @ordmiss

Absolutely amazing collaboration from year 10 today. 100% engagement and constant smiles from all #lovetsla #spiral @strykerstennis

Students show better Interpersonal Writing skills than Speaking via @SpiralEducation Great #data #langchat folks!

## Get the Clip Chrome Extension & Create Video Lessons in Seconds

Add Clip to Chrome