# Part 2

More Options: Make a Folding Card

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#### Storyboard Text

• a is the coefficient in front of x2, , so a = 1. b is coefficient in front of the x, so here b= 4 c is the coefficient, or the term without any x next to it, so here c = -21  So, now we plug it into the quadratic formula.
• Joey Helping Arianna
• The quadratic formula helps you solve quadratic equations. First we need to identify the values for a, b, and c (the coefficients). First step, make sure the equation is in the format from above,  ax2 + bx + c = 0 x2+4x-21=0
• ﻿Joey's Work
• x= −4±√16−4⋅1⋅(−21)​​ _________ 2 x=  -4± √100      ________ 2 -4±√100 _______ 2
• x=  -4± 10 _________ 2 = -2 ±  5 x= 3 or x= -7
• Ohhh.﻿ So basically, you have to turn the equation into  standard form, then  plug in the  equation into the quadratic formula and then solve.
• Arianna Trying to Understand ﻿
• ﻿Yea. I could have just explained it like that, but now you understand. But to make sure try number 2.
• Joey is explaining the basics for the quadratic formula.
• Math Problem ﻿
• Joey started to solve the problem step by step, showing Arianna how he solved the quadratic equation.﻿
• ﻿Arianna Solving the Problem﻿
• 3x2 +6x = -10 -> (3)x2+(6)x+(10)=0 x= -6±√62-4(3)(10)                                   x= -6±√36-120      ____________                ->                   ______________          ->                          2(3)                                                                                       6 -6±√84 _______           = x              6
• Arianna seems to get it, but now she needs to try it on her own. ﻿
• ﻿Joey Checking the Work﻿
• Wow! Yes. This is correct. Good Job! You see. All you needed was to see the work step by step. Plus you had a great teacher *cough cough* me.
• Arianna looked at her paper and noticed that she needed to first put it into the format : ax2 + bx +c = 0﻿
• 2.       3x2﻿+6x= -10
• Arianna noticed ﻿that she can’t take the square root of a negative number without using imaginary numbers, so that tells us there’s no real solutions to this equation.  This means that at no point will y = 0, the function won’t intercept the x-axis.
• Arianna finally understood the quadratic formula. She understood when there is a solution and when there isn't, which can be tricky, but she got it. Yay!
• OMG!! Yay. Thank you Joey for helping me. I really needed this. ﻿
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