09 - The Quadratic Formula Explained, Part 1 (Practice Problems & Solutions)

View more lessons at www.MathAndScience.com.
In this lesson, you will learn what the quadratic formula is, how to use it, and why it is important to solve quadratic equations in algebra.
First, we will derive the quadratic formula using the completing the square method. Next, we will solve numerous quadratic equations using the quadratic formula and check the answers.

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Bro your 35 and studying quadratic formula I'm 14

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[@YourWrongImRight933]

@@akramshaheen2481 bro you’re 14 studying quadratic formula im in 7th grade

[@jonnukisan9759]

Now I'm glad that I learned completing the square before learning the quadratic formula! You made it so clear how they are derived. Thank you, great punch line

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[@zhengzhang3903]

One thing I would like to mention is that 15:33 if a is negative, and you take the square root of 4a^2 you can get -2a. But since there is a plus or minus sign in the front, it does not change the form.

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[@smendetv1105]

A blow by blow account of the derivation...much better clear as daylight

[@MathAndScience]

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[@MathAndScience]

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[@user-yc6rd5pq9e]

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[@ritam20071]

This method is called Sridharacharaya method discovered in 10th century AD by Indian mathemetician

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[@rubiegamble898]

I'm trying to get my GED and I need to learn the Quadrtic Formula.

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Can you prove the quadratic formula? Jason, here is an idea for you. Why not make videos in terms of math proofs? I am sure that math majors would love you for it.

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Welldone 🎉

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[@sandrarr5434]

Hello there I'm studying the AQA foundation and I wondered if you could tell me how does one know when to apply the Elimination process t o simultaneous equation and when to apply substitution what is the distinctive different that I should know please.? Is it when there's an X Square coefficient

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[@fathoy1]

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[@Yesmayo1982]

why is b/ax divided by 2 then squared? WHy not do the same with x squared and -c/a?

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[@user-yn3ev1oy1j]

At 7:58 why do you have to divided by 2 and square root answer please I need really help please I hope you reply.

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[@lauren9004]

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[@stanphiri2341]

Amazing

[@user-yn3ev1oy1j]

At 7:58 why do you have to divided by 2 and square root it pleases response I hope you see it

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[@MathAndScience]

You are welcome

[@johnmaulkin-ur8lm]

Fantastic job but i am confused; at 13.19 mins. b/2a.x + b/2a.x = b/a.2x. Please help. Thank you.

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an endless accordion of whiteboards! awesome

[@sawdustwoodchips]

Completing the square allows you to find the turning point of the quadratic.

[@stevenscottoddballz]

3:52 I keep hearing "Always get 2 solutions", but when I did [3A² = 6A - 3], there was only ONE solution.

[@jozef-aerts-wiskunde]

You have 2 , 1 or 0 solutions , depending on the value of d^2 -4ac ( called discriminant )

[@stevenscottoddballz]

@@jozef-aerts-wiskunde I am VERY familiar with the discriminant. I have had trouble with [S² + 7/4 = 1/2]. I don't know what to do with the 2 in the discriminant.

[@apoll0626]

why do you prime factorise

[@theophonchana5025]

b^(2) - 4ac = 13

[@ChavoMysterio]

Here's a fun fact about me: I first learned about the quadratic formula in Geometry.

[@ownagebox]

at my time we only learnd the pq-formula

[@theophonchana5025]

b^(2) - 4ac = -36

[@vaibhavsingh8361]

Quadratic Formula is Known as Sri Dharacharya Fomula Which is Derived from Indian Mathematician

[@theophonchana5025]

b^(2) - 4ac = 20

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@Jason Gibson

[@MathAndScience]

Thank you so very much! I really appreciate the kind words!

[@Koreanbosuji]

@@MathAndScience :-D Anytime - welcome

[@Ihuoma307]

Waw nice

[@theophonchana5025]

#QuadraticEquation

[@clairgarrick9842]

I always forget how to derive the quadratic formula from completing the square.

[@TheByzmal]

(Ques) I 15 min & 35 secs. Why did you square root the denominator & not the numerator.? You only square root 4ac^2 & not the terms above it. Why?

[@MathAndScience]

I did take the square root of the bottom. The answer was 2a.

[@TheByzmal]

@@MathAndScience I see & know that, I am asking about the top. Why didn't b^2 - 4ac became b - 2ac?

[@solomonigba2580]

I have some questions here

[@theophonchana5025]

sqrt (-36) = error

[@khalilfuller4939]

i root

[@theophonchana5025]

a = 3 b = 1 c = -1

[@zbigniewbrzezinski8869]

You forgot -1 on the equation ! (First example)

[@theophonchana5025]

y^(2) - 4y + 13 = 0 y = (- (-4) + sqrt (-36) ÷ 2 y = (4 + sqrt (-36)) ÷ 2 y = error

[@khalilfuller4939]

So it will be +/- 6i

[@khalilfuller4939]

So it will be +/- 6i

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[@jessethompson8606]

@19:28 oh it is definitely still considered some form of black magic..

[@user-ic3dn3vu9u]

this formula is called shree dharacharya formula

[@nickmasters6239]

stop looking at the comments and look a the video

[@theophonchana5025]

a = 1 b = 6 c = 4

[@theophonchana5025]

sqrt (-36) = invalid input

[@MathAndScience]

You need to get a calculator that can give you a result that is an imaginary number. When you take the square root of a negative number a regular calculator cannot compute the answer but a scientific calculator will give you an imaginary answer which is the correct answer.

[@kainacorsiga3590]

Oh

[@Tarzanaxx]

Square root of. 20 IS NOT 5. ERROR IN EXAMPLE.

[@Tarzanaxx]

Square toot of 20 is 4.47…

[@nripeshkumarmishravinayak664]

SRIDHARACHARYA RULE

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this was not a good this shit made me more confused

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