Solving quadratic equations by completing the square | Algebra II | Khan Academy
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- Опубликовано: 2 окт 2024
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Solving Quadratic Equations by Completing the Square
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Algebra II on Khan Academy: Your studies in algebra 1 have built a solid foundation from which you can explore linear equations, inequalities, and functions. In algebra 2 we build upon that foundation and not only extend our knowledge of algebra 1, but slowly become capable of tackling the BIG questions of the universe. We'll again touch on systems of equations, inequalities, and functions...but we'll also address exponential and logarithmic functions, logarithms, imaginary and complex numbers, conic sections, and matrices. Don't let these big words intimidate you. We're on this journey with you!
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For free. For everyone. Forever. #YouCanLearnAnything
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Why can't we just listen to these guys videos in Math Class? In just 14 minutes, he taught me as much as two algebra teachers taught me in (no joke) six hours!
Math Teacher Logic
*Gets help on confusing topic* C'MON GUYS WHY DON'T YOU PAY ATTENTION I TAUGHT THIS IT EASY!!!
"any questions" says the math teacher. *silence* CMON WHY IS NOBODY ASKING QUESTION THIS IS HARD STUFF
+Misha Bjerken I take all my classes normally but I take math online. I can't understand any of my public schools math teachers so it's just a waste of time. I wish online school was how everyone was taught, it honestly saves so much time, because you can go at your pace.
Because then they will be boring because they will be more forced and concentration will be impossible because everyone else is talking over. The teachers are bad teachers, but the class is usually a bad class or at least in my experience.
@@BlackHatChannel really true Sal proves every formula and explains a lot better than all other teachers
You're 20 now. What's the state. How are you doing. What's going on.
Khan Academy: Helping kids with shitty teachers since 2006
@FredTheBread well then this comment is not for you...
this helped a lot more than my Algebra teacher
Same.
Me in 7th grade= This is easy!
Me in 9th grade= What is this witchcraft?
Me after watching this video= This is easy!
Sup shaurya. This is vishnu from nps yelahanka. If u remember.
@@rain7870 what's creepy??
Ever since the 9th grade this channel has been getting me through my math subject. Bless this man 😩 thank you so much haha
If there was only one in biology I wouldn't be in borderline D
+Penguin YES This video pretty much saved my sixth grade gpa
@@amon7816 Khan Academy also covers Biology concepts as well!!
this man is single-handedly carrying me through sophomore year
same dude my math teacher like speedruns our lessons 😭
I'm so glad things like this exist. Having been thrown into a room with someone who's a sorry excuse for a teacher teach you makes this stuff impossible.
I hate quadratics
Thanks for picking up on my math teacher's slack. 💗
Honestly same
Mikaela Kozechik same
I am in 9th grade and you sir just saved my life.
+KhalidHamid50 yo me too
Me too. Lol
saaaaame
I learned this in 7th grade
Pixeled Opper Yeah, you don't need to be a punk about it. Go brag somewhere else.
we should have a holiday for you
Honestly my teacher is fine...I just didn’t pay attention.
My teacher played a buffering old video in class that no one understood so I went to khan academy like always, teaching me more than my teachers since day 1
Dan Ab are you physically an advertisement?
Akira Douglas maybe
WHY DA HELL IS MY TEACHER TELLING ME I NEED TO MASTER THIS WHEN I AM IN ALGEBRA 1?!?!.
because this will be so much useful in calculus
My brain just turned into a gelatinous pile of mush.
Congratulations.
Can you replace my math teacher please? I finally understand this! It's like I've learned the secrets to the universe! Is this how people who understand and enjoy math feel 24/7?!
10 years life and you sir are still saving 9th graders lives. 😂😂😂
khan academy is one of the best things ive encountered in my life
bless this channel
Thank you so much! My Algebra 2 teacher is Romanian and English is literally her fourth language. As you could imagine, she isn't the greatest teacher on the planet. I really appreciate it!
Khan academy has saved me so many times now
This man can teach me all these things in 15 mins than my teachers could in a few hours.
Thank you so much for this video, I was having lots of trouble with this process, but now it has cleared my mind!! Thanks again!!👏🏽👌🏽⚡️🔥😇
Seriously, Sal, I **love** your work! Thank you.
thank you khan academy!! my girlfriend and i couldn’t cook pizza and we couldn’t complete the square either!! BUT YOU HELPED US SOLVE ONE OF THOSE PROBLEMS :))
Do people appreciate the genius of this method, and how everything just works out?
Sal Khan is such a life saver. Literally helps me with everything, history, science and Maths. I have no problems with English.
YT - Rhianna A colon, (:), should have come after 'everything'. You're welcome.
Nationale Sozialistiche Deutsche Arbeiterpartei *leans into mic* wrong
Where does the +/- come from @4:10? Many thanks
Arun Prathapan the number can be either positive or negative because a negative number times by itself is a positive. Eg: -3 squared equals 3 squared, therefore a square root can be a positive or negative
I hate math, why do i have to study it WHY
shaikhah - My Friend, mathematics is completely logical, you just have to know how to solve the equations. As to why you have to study it, you’ll find out in a few more years.
Yeah i hate math too but math is everywhere so we need to study more about it
Love it when my math teacher doesn’t teach us how to do this and gives us a test today !!!
You're good keep it up :D I didn't understand everything at the start but I got it towards the end Thank you very much you superior human being
The only reason I still like math my teachers are o useless ily Khan academy
this was a lifesaver and I have a test in 15 min 😭
How’d it go
Did you pass?
They passed away
DA Boss you are going to help me pass math!!!!!!!!! im trying not to hate it right now
thank you sal for everything you do. i came across your videos some point in elementary school because we had khan academy and now im in 12th grade! the videos my algebra teacher gave me are horrible so i decided to watch yours instead lol
I did not understand at all
not this vid
Dividing fractions, as easy as pie,
Flip the second fraction, then multiply.
And don't forget to simplify,
Before it's time to say goodbye
brenda whitman Ita because he doesn't explain it well. if I had not known how to do this before watching this video, I would be confused as well.
He explained it just fine, it's just hard for the mentally challenged to understand.
ZATIONS wow.
im jn algebra 1 in seventh grade and lemme just say THANK YOU SO MUCH
I just finished algebra 1 and I'm moving on to geometry, my teacher gave us a packet for math to do over the summer and I don't think they ever taught us this.
I wish we just watched your video during math hour. Much easier to understand
Thank you sir. This was our second math lesson in 9th grade and you made me understand it more!! Thanks :D
I’ll be honest, I did not understand a thing. This is the only vid I couldn’t understand 😭
thank you very much sir, you are the hope raiser for me to make me believe that I can do math😄😄
khan u are tge BEST of all
Dear Math,
I am not a therapist, so solve your own problems.
Thank Khan Academy, what took my teacher 2 hours to explain and to get our class to understand; only took 5 minutes with this video. Now that is an accomplishment.
why dont you have ads on your videos??!! you would be making bank! and possibly having this as your carreer!!
lol this is his career, he aims to provide this service for us free of charge, because learning should be free. Search "Khan Academy Ted Talks" on RUclips to find out more about him, his organisation and their objectives
Well i mean it is still free to us even if he did put ads on
I finished the video and still doesent understand anything
u r actually a hero
Missed the lesson on this & reading the textbook doesn't help. Thank you (:
better and more polite than my teacher
youre the besttttttttttttttttttttttt thankssssssssssssss
youre my online math teacherrrr.
best teacher in my life
its 2022 n this is still useful
Math test tomorrow on this stuff... I may as well not even show up... Too hard
I have ADHD and yet still I've learned more from these guys in this video than I have in algebra class throughout the whole unit on quadratic equations
thank you so much for this sir
exuse me we can use b^2_(4.a.c) it is easy and time between 5 and 20second
thank you soooo much!!
very helpful
This video is AWESOME. What calculator app was that you used at 11:21
This says algebra 2 . So I've been taking algebra 2 things in 8th grade... wow I'm so mad rn
ATTENTION EVERYONE WATCHING AND CONFUSED: go watch patrick jmt vids they're much more comprehendible
Great video. Thanks for sharing
I'm learning this in algebra 2, but it also came up in my algebra 1 class if that helps you
Completing the square is too difficult.
Useless outside of a textbook. How often in the real world do you actually see perfect round numbers?
I'm at 1st year college right now lmao
THAAAAANK YOOOUUUUUU!!!!!!!!!!
Is there a way of clicking the like button multiple times?
+RazorMink Haha don't worry i found that a long time ago :P
2:50 is it 2ax = - 4x or - 2ax = - 4x ?
I still dont understand😭
OMG did u know? all the modules and reference books didnt have this method here. however i thought that completing the square was difficult but i found ur method to be easy. so i used it and wala i got it right! im so happy cuz sincd last year whenever theres a question on completing the square ive been skipping it. thnk u
How come you stuck a four in that gap instead of dragging the neg five there? Totally don't understand this.
mousehead2000 if you stuck a negative five in it won't be a perfect square
Half a million views and only 500 likes...
+john greene Thats because most people watch it on the Khan Academy website itself
+razlight789 Yeah. I usually go on the website, but when I watch on my iPad, I go on YT because the Khan Academy app keeps crashing.
I think you used negative sign here ; (x-a)square . So isn't it that a=2 not -2 ?
I think he shld use (x+a)square in that case. So that a can be equal to -2
I got more confused and my test is in 30 mins :(
Dimensions of Triangle and a Rectangle? How?
x^(2) - 4x - 5 = 0
(x - 5) (x + 1) = 0
You save me. Thank you
at 5:20 why did (x-5)(x+1) get become x=5 and x=-1 and not x=-5 and x=1 like in the problem?
cause either (x-5) or (x+1) has to equal to zero as (x-5)(x+1) = 0. Meaning that whatever you put in x, the expression has to equal zero.
I watch other videos and it makes sense, but I feel like I need to watch a Khan academy video multiple times and even then I don't get it. Wondering what the mental block is...
where does the +/- come from @ 4:10 ??
can you help me to solve 10m^2x^2=40n^2p^6 using quadratic equation by extracting the square roots.....give me a complete solution please
No thanks
No thanks
one of the few of your videos where I come out more confused than how I came in
Which category is this
the 2nd one was confusing but I can get this down easily even trigonometry isn't that hard to me, i just need to pass this placement test by next week.
Express x in terms of y
.
What is the name if this type of questions?
Do khan academy have the video?
So rearranging? That's a lot easier than stuff like completing the square if you know how to do it
changing of subject. they definitely have videos on it
Maybe now I won't make an F, lol
THANK YOU MR KHAN. YOUDAMAN!
arrrrrrrgh. im having probs cuz i cant figure out how to solve the formulas...(no numbers, juz letters) :( if you have a vid on this, or can help me, let me kno :((
THANK YOU!!!! This helped me study for my test
Btw I got a 100 on that test
@@helixshark1753 6 years later but congrats on 100 :D
why in the min. 4:30, you put + or - 3? you just square root the 9 into 3 in the last step
Im 8th grade WHY im here
gg bro gg
TFW when you doing 12th grade integral calculus but don't remember the fookin completing-the-square method no mo' (ᕵ﹏ᕴ)
the first equation the answers are 1 and negative 5 not negative 1 and positive 5
@destinyjorenby yes like this a=bc2/4ac and you wanna know what is c? but more complicating
What if the equation is 2x(square) - 7x =-3
That’s nifty.
i loved math til algebra came in.
im given a lot of problems where 3x is a fraction... this wasnt helpful.
what the flip
Why was someone with a NAZI handle critiquing others for being unkind? I had to report him.