Solving quadratic equations by square roots | Algebra II | Khan Academy

Solving Quadratic Equations by Square Roots

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[ashiyaprowell]

I’ve never been so confused in my life

[ducktape]

Thank you so much I was peeing during my math online class when the teacher discussed this ;-;

[thmanrailfans]

I learn nothing from my teacher. I learn faster from an 11 minute video than a 52 minute lesson

[Chaosflyex]

Hi Mr. Khan, thank you very much for doing this for the millions of people out there watching your videos. I'm taking Algebra I and this is helping a ton! I always move towards your videos when I am about to learn something or don't understand a new concept. God bless you, again I truly thank you very much. Keep up the amazing videos! ^_^

[cyodissnips]

Me at the end of the video not understanding any of it: wut
Him: Well, that was a good warm up

[OffTheBeatenPath_]

Really poor example to use the square root method.

[-smp-scientificmethodpersp]

@5:13 for those of you who got lost, because he didn't explain what he was doing. He substituted one of his solutions for the x in the original solution, because he had solved for x. Since he solved for x, he can substitute what he solved for instead of using x. X=solution to be replaced with in substitution.

The answer to the solution is to find what = 0. Well, 0=0, so you have to prove that. In order to prove it, you need to get get rid of that unknown variable that needs to be solved for. In this case, it's x that is the unknown. So what do we do in algebra? Find X! After we know what x is, we can solve the original problem by replacing that x (unknown) with what we solved x to be (now known). Now we can solve the original problem. The original problem is 0=0 and you have to solve for that. The square root part in this video isn't to solve the problem (0=0). The whole square rooting part is to solve for x (X=?). Then use the answer for what x is to solve the original problem.

If you still don't understand.... Yikes! Go watch some pre-algebra videos.

[heyitsjaee]

my brain has so much smoke coming out of it 😐

[VanNintendo]

You are awsome! You have helped me so much whenever I have a test!

[teachmechannel]

Thank you so much for this great lesson. I was searching so hard for this kind of extracting square root, then I found this video. THANK YOU SO MUCH😇

[jlklai]

If only my teacher could be as good and clear in Algebra as Mr. Kahn. Thanks for the little clarification!!!

[debo]

Imagine this, but explained MORE complicated than it should be. Thats my teacher y'all

[nightowl]

It's been 11 yrs but generations still use it till now

[anshugupta]

Sir please make a video how to factroise. √3x² + 10x - 8√3 = 0

[sarahskup]

THIS HELPED SOOOO IM IN 7TH GRADE AND AM TAKING ALGEBRA 1, BUT I PROBABLY WOULD NOT HAVE PASSED PRE- ALGEBRA WITHOUT THIS YOU RULE MR. KHAN

[dollyspine]

helping me pass my final exam tomorrow, THANK YOU

[Tenshar]

Thank you so much, because it was just not clicking with me at all....God bless you!!!!

[airasagmon]

im from philippines Thank u sm
I might Ace the math exam tommorow thanks to u😂

[Mark-jhmt]

Thanks! Helped me alot, the last two equations are not taught to my class yet so i might get a head start from this! Thanks again!

[bananiaman]

Thanks a lot! This really saved my a$$ :)