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Completing the Square - Best Explanation

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  • čas přidán 16. 10. 2012
  • Explains how to solve quadratic equations by completing the square (also called the square root method).

Komentáře • 277

  • @krampus8362
    @krampus8362 Před 6 lety +12

    Happy to see a teacher that can actually teach. Most teachers on youtube, or even at schools, do not know how to explain to students.

  • @mikefule330
    @mikefule330 Před 5 lety +38

    Excellent explanation. What makes it so clear is that you "factor" the modified expression to show exactly why the 25 is in there. Most people don't include that part in the explanation. Understanding how and why is so much better than trying to memorise a series of stages that make no sense without context. Thank you.

  • @DPR_JIN
    @DPR_JIN Před 6 lety +168

    Deffinetly better than ur prof , straight to the point . It feels like a private lesson 😂😂😂

    • @tajamulsir9620
      @tajamulsir9620 Před 6 lety +1

      i have also explained this method in more easily .. watch on my youtube channel .. Tajamul Sir ..

    • @BobBob-uv9fq
      @BobBob-uv9fq Před 2 lety +3

      I’ve just had a private lesson ,and still can’t do it

  • @Acw279
    @Acw279 Před 6 lety +81

    OH MY GOD THANK YOU. All the other videos didn’t make any sense. Bless your soul. Your username is true.

  • @Dorddis
    @Dorddis Před 6 lety +175

    why is this 480p vid lookin lik a 1080p one?

  • @isabelfowlkes708
    @isabelfowlkes708 Před 6 lety +11

    Thank you so much!! I looked at like 5 different videos and none of them made any sense to me until this one!! All of the others just beat around the bush and did some weird method that took like ten minutes. I wished I could give 20 thumbs ups. You've got a new subscriber!

  • @shreyabasu6199
    @shreyabasu6199 Před 5 lety +10

    You actually are better than all the professors I've had combined.

  • @larrywiener6327
    @larrywiener6327 Před rokem +4

    Great explanation! One thing I would add at the end. 32 is 16 * 2. Therefore, after the plus and minus we can put four times the square root of 2. That would be in a more simplified form.

  • @mayahamandi4754
    @mayahamandi4754 Před 5 lety +8

    THANK YOU! This helped me so much with studying for a test. No other video explained it like this and i was completely clueless. You explained it so well and made it so much easier to understand!!

  • @fatimaalamien8786
    @fatimaalamien8786 Před 6 lety +36

    U r actually better than my prof😂😂

  • @spiderslogan2617
    @spiderslogan2617 Před 3 lety +1

    You breaking it down is beautiful, thanks for the help. You're an angel! you didn't leave anything out and you answered ALL my questions thoroughly. sorry I'm 8 years late lol

  • @derro8314
    @derro8314 Před 6 lety +26

    There’s five methods actually...
    Isolation
    Quad formula
    Diamond
    Complete the square
    Grouping

    • @benisman
      @benisman Před 4 lety +28

      6. Giving up

    • @ayushkishor3207
      @ayushkishor3207 Před 4 lety +2

      @@benisman underrated comment

    • @Surfing566
      @Surfing566 Před 4 lety

      @@ayushkishor3207 for real

    • @dotzonzab5132
      @dotzonzab5132 Před 3 lety

      I just want 3 it's too much for me

    • @derro8314
      @derro8314 Před 3 lety

      Summer class Gaming WOAH TWO YEARS AGO LOL quadratics are easy as you get higher and higher in math

  • @angelgracedorde6189
    @angelgracedorde6189 Před 6 lety +15

    i love it. i like how you explain things so gentle for us to understand better thankyou

  • @gcebilevilakati1322
    @gcebilevilakati1322 Před 6 lety +15

    This video had all the steps explained carefully and well. It has really really helped me. THANK YOU !

  • @ChetanKania
    @ChetanKania Před 3 lety +3

    what happens when your "B" value doesn't give a good number when dividing by 2? For example, what if the B value is 15 or 9 or 33?

  • @conohanfamily
    @conohanfamily Před 2 lety +1

    Check out Mind Your Decision's explanation of quadratics using geometry. It visually shows "completing the square" making it concrete why you take half of b and square it. Really neat way to see it.
    This was still very good. Putting the two together is helpful.

  • @fatimaalamien8786
    @fatimaalamien8786 Před 6 lety +12

    BEST EXPLANATION EVER♥️

  • @Eric_412
    @Eric_412 Před 4 lety +1

    They say a topic isn’t fully understand until the person can teach it, yep, this guy understands it, makes it look oh so simple 🙀🙀😳😩, is a really good video..

  • @aya-lt7ll
    @aya-lt7ll Před 2 lety +1

    this video is 9 years old, wow i hope this person is doing well in life and im wishing them the best

    • @stuartbowman_
      @stuartbowman_  Před 2 lety +1

      I'm good :) So glad these videos are still useful to people

    • @aya-lt7ll
      @aya-lt7ll Před 2 lety +1

      @@stuartbowman_ OHMYGOD,,, you replied! glad to hear that! and yes this was very helpful, thank you so much!

  • @Krazycutiegurlxxx
    @Krazycutiegurlxxx Před 8 lety +11

    My gods. I was so confounded as to why we were doing all that stuff to b in ax^2+bx+c=0.
    I don't know how i didn't recognize the perfect square before!
    Why do so many math courses insist on just telling you how to get the right answer without explaining how it works or what the underlying concept is?!
    It makes so much sense now. I'm ashamed for not realizing it all right away.
    I wish i could give this video more than one thumbs up.
    My gods...

    • @Krazycutiegurlxxx
      @Krazycutiegurlxxx Před 7 lety +1

      twistedblktrekie I've been homeschooling myself alone with books and online resources for over a year now. The internet and myself are the best teachers i've ever had.
      Math teachers would practically never explain anything. I went to a public school in a ghetto too, so, that also probably didn't help.
      I can hardly wait until i start calculus. I never imagined that i would actually love mathematics.

    • @Krazycutiegurlxxx
      @Krazycutiegurlxxx Před 7 lety +1

      twistedblktrekie I learn in a similar way, but for me, if it doesn't make sense to me conceptually, i'll have more trouble recalling it, and i'll get frustrated, so, i usually don't move on until i understand the concept adequately at the very least (by my own judgement i suppose, but hey).
      Luckily, the concepts often aren't difficult for me to understand at all, but i'm only on algebra 2 right now.
      I desperately want to be a physicist. I don't know if i can, or if i can even get into a good university due to my past and the circumstances my past has put me in. But it's what i want anyway. I'm 19, so i'm already very behind too.

    • @Krazycutiegurlxxx
      @Krazycutiegurlxxx Před 7 lety +1

      twistedblktrekie My mom is a nurse; knowing what i know, i would never ever get into medical. Physics is my dream. It has been since 1st grade. I'm just not giving up because there isn't much else i want out of life aside from that anyway, aside from my dogs and some video games. Money doesn't matter much to me as long as i have those 3 things and sustenance, basically.

    • @Krazycutiegurlxxx
      @Krazycutiegurlxxx Před 7 lety +1

      twistedblktrekie Honestly, i only took half a course in quantum mechanics before i decided to stop and go learn the math first. But, that half a course changed the world in my eyes, and i feel like it's something i'd like to put my life into. I loved physics since first grade; i just didn't know it before about a year and a half ago.
      There are a lot of good physics courses online, and a lot of good books if you're interested. I personally would recommend the Feynman lectures firstly.
      Wish me luck... I'll probably have a hard time getting into a good university, but, i suppose i'm too dense to give up.

    • @Krazycutiegurlxxx
      @Krazycutiegurlxxx Před 7 lety

      twistedblktrekie It depends. There are jobs in universities, in companies, and for the government. The university jobs are the best; and the most difficult to attain. I do not want to work for the government, but company jobs can vary greatly. I want to be able to do actual research though.
      I really need to get into a top school, at least for grad school. People who go to just any old university for a physics major seem to always end up in a cubicle farm doing work that their heart isn't in.

  • @sarameeks4493
    @sarameeks4493 Před 3 lety

    THANK YOU. Geezus. I'm a grown adult taking a business math class, and I'd forgotten how to factor that out. After two days of watching videos and reading books, this finally clicked for me. Thank you thank you thank you.

    • @chocolateangel8743
      @chocolateangel8743 Před 3 lety

      Completing The Square really makes sense when you see it done with the area model. It because obvious why the middle term is divided in 2 and squared. A Quadratic is a square, geometrically-speaking. The reason you divide the middle term in 2 is because each side lengths have to be the same. You square it because you are literally adding a missing square units (length X width) to the larger square to make it whole. One thing I've learned about math is the more you understand (concepts and mathematical logic), the less you have to memorize. Math is just the language of numbers. Good luck in school.

  • @JG-ld6cf
    @JG-ld6cf Před 6 lety +3

    Thank you so much! I've watched so many videos and this was the only one that made sense! Thank yooooooou

  • @Aditya-hk4je
    @Aditya-hk4je Před 4 lety +2

    Bruh this guy is a genius he deserves more subs

  • @PRADEEPKUMAR-bw6qf
    @PRADEEPKUMAR-bw6qf Před rokem

    Seeing this video after 10 years but then also a life saver and by following the rules of algebra, this equates this video to a legend
    #THANKS BRO#

  • @seikopatton4782
    @seikopatton4782 Před 4 lety

    THANK YOU SO MUCH. Your video was the only one that made any sense at all. You put Khan Academy to shame! ;) God bless you!!

  • @e.k_desaint
    @e.k_desaint Před 6 lety +4

    Oooh so good!!!! Even at my higher level of study I still had issues but these video has helped me
    So far I'm now good!!

  • @mixed-math8216
    @mixed-math8216 Před 2 lety

    Dude, you are literally a legend! tysm for the clear explanation, the best I could find on YT so far!

  • @fauziamahmood4522
    @fauziamahmood4522 Před 6 lety +1

    BRO, thank you! you saved me from getting a 1 hour detention!
    you definitely better than my prof thaaaaaaaaaaaaaaannnnnnkkk yoooooooooooouuuuuuuuuuu

  • @isnansunuyuntaro2974
    @isnansunuyuntaro2974 Před 6 lety +2

    The best explanation so far

  • @billendy7425
    @billendy7425 Před 4 lety +5

    I know this is a relatively old video, nonetheless, I found it very helpful and was finally able to connect some concepts. Thank you.

  • @jeimizuki4938
    @jeimizuki4938 Před 6 lety +3

    could you do a video about rational functions, equations, and inequalities i'm having a hard time dealing with complicated problems but you're videos always helps out. thank you very much :)

  • @martinohare1936
    @martinohare1936 Před 6 lety +1

    This is the most rationale explanation I have seen. Moreover, the narrative can be said to be measured, natural and straight to the point. Impressive way of reassuring learners whilst going through the steps in a clear and humble manner. In short, the video is about the subject and not about 'creating a personality or show' to pseudo entertain. Love this method of calm step by step explanation.Could there be a similar video, but of the type where the x squared term has a leading co-efficient?

    • @stuartbowman_
      @stuartbowman_  Před 6 lety

      Great to hear, thanks man. No I don't have any videos specifically about that, but you can always divide both sides of the equation by whatever the leading coefficient is to eliminate it. If you proceed from there with the same method, it won't be pretty but it'll work. Cheers

  • @edwardfknight
    @edwardfknight Před 2 lety

    Best explanation on CZcams. I remember being confused on this when I was in 10th grade.

  • @mbongeninkosi3852
    @mbongeninkosi3852 Před 6 lety

    Im south africa and ive just subscribed and pressed d alert button. U d best man. Better dan those plastic professors LOL

  • @abdulrazaqyahaya01
    @abdulrazaqyahaya01 Před 5 lety +2

    Your lecture is quite intelligible, I'm very glad, thank you

  • @Azami0001
    @Azami0001 Před 5 lety

    You have no idea how much I love you

  • @Smarion2
    @Smarion2 Před 5 lety +1

    Thank you SO much. I am studying for my CSET and this is the only one that breaks it down the way that makes sense. I couldn't figure out what the point was in using Completing the Square when we can factor or use the Quadratic Equation. Other channels say "If a is equal to 1, add b/2 squared and it completely threw me off. But, what if a is not equal to 1?

    • @jamilashekh3509
      @jamilashekh3509 Před 4 lety +1

      Then you divide all the numbers by the a
      FOR example 2x² + 10x = 0
      You do 2x²/2 + 10x/2 = 0

  • @stuartbowman_
    @stuartbowman_  Před 11 lety +8

    You're welcome! Glad it made sense

  • @andrewmiguelvirtudazo1953

    OMGGGG THANK YOU IVE BEEN STUCK WITH THIS FOR 9HRS BUT NOW I UNDERSTAND GOD BLESS YOU I WAS ABOUT TO CHECK YOUR OTHER VIDEOS BUT YOU ONLY HAVE *VIDS WE NEED MORE PEOPLE LIKE YOUUUUUUU AAAA THANKASSASAS

  • @Sirishaw-vu5se
    @Sirishaw-vu5se Před 3 lety

    i literally watched 40 videos prolly but this one is the only one i understood by watching it ONCE

  • @gleon1602
    @gleon1602 Před 5 lety +26

    √32 is reducible to 4√2.

    • @leonelfederico245
      @leonelfederico245 Před 2 lety +1

      I was wondering about that. Is it considered incorrect if the reduction is not completed?

    • @pinkman17_
      @pinkman17_ Před rokem

      @@leonelfederico245 i dont know

    • @ooolol
      @ooolol Před rokem +1

      ​@@leonelfederico245 it's considered incorrect.

  • @JackKnife2730
    @JackKnife2730 Před 6 lety +4

    your S's sound like a blow off valve, good video clears all of the confusion i had up.

  • @jakesnell7707
    @jakesnell7707 Před rokem

    Dude the way you teach is fantastic… you really give thought to what some people may or may not know! Thank you so much!

    • @stuartbowman_
      @stuartbowman_  Před rokem

      Thanks! Back when I made these videos I was tutoring math every day so I had lots of practice

    • @ChocoMilk.o_o
      @ChocoMilk.o_o Před rokem

      @@stuartbowman_ Oh my gosh, I had thought you left, your tutoring level is so much better then anyone I find on youtube and they try to make it look cool with graphics but you doing it on paper really makes it feel like authentic maths! I wish you would come back

  • @dalynnthreadgill4227
    @dalynnthreadgill4227 Před rokem

    If the leading coefficient is > or = 2, how would I go about solving the equation? Say 3x^2 - 12x + 9

  • @shalomumayanga3410
    @shalomumayanga3410 Před 5 lety

    You are the best mathermatics teacher

  • @yaseenalaraimi1919
    @yaseenalaraimi1919 Před 2 lety

    I'm so slow at learning this kind of stuff but when I saw this I got it straight away

  • @colinjava8447
    @colinjava8447 Před 5 lety

    I can think of factors that multiply to give -7 and add to give 10:
    5 + sqrt(32)
    5 - sqrt(32)
    The point being, just cause something can't be factored using integers, it doesn't mean it can't be factored.

  • @PJade
    @PJade Před 4 lety

    That is the best explanation of completing the square I've heard. Bless you sir!

  • @mikefule330
    @mikefule330 Před 5 lety +4

    "I can't think of any factors of 7..." It's a prime number!

    • @zeyadular
      @zeyadular Před 3 lety

      @Matthew Bair Yeah, that' a Prime number.

  • @stuartbowman_
    @stuartbowman_  Před 11 lety +37

    Glad I could help

    • @user-in9of6os2c
      @user-in9of6os2c Před 3 lety

      I just have one thing to ask why did you cancel the -7?

    • @user-in9of6os2c
      @user-in9of6os2c Před 3 lety

      And like would that happen in like any question with completing the square

    • @cheechierocks
      @cheechierocks Před 3 lety +1

      @@user-in9of6os2c ... yes... you have to move the end coefficient to the other side in order to make a perfect square on one side... but also note you have to add the new coefficient to both sides in order for the equation to balance. As you can see, he’s not done anything that unbalances the equation. Eg, he hasn’t added to one side, that he hasn’t done for the other... I hope that helps. The formula he gave is ‘B (middle coefficient of x) divided by 2 and squared’. So, half of 10 and squared = 25... then add 25 to both sides. Also remember, X is one side of the equation and Y is the other... on your graph, you have X axis, positive & negative, and Y axis, positive and negative.... thus a squared graph, and why the expression is completing the square. After you’ve solved the quadratic equation, for X & Y, you can then plot or plug in the numbers onto your graph... it looks hard, but when you know how and why it’s used, it’s actually a work of genius.

  • @tony9622
    @tony9622 Před 5 lety +1

    what if you had an equation where you have to divide by a negative like -4b=64

  • @lianedweinpinto3867
    @lianedweinpinto3867 Před 5 lety +1

    What if the linear term is negative when we are going to found the square root of it.Can I square root it even it's negative?

  • @tomdryan
    @tomdryan Před 6 lety +1

    Thank you for taking the time to explain each step (even the "dumb" ones). Other videos we watched on this subject glossed over the "obvious" steps, making them impossible to follow (giving me flashbacks to some of the really bad math teachers I've had). My son was able to complete his math homework, thanks to you!

  • @jolietess4126
    @jolietess4126 Před 4 lety

    finding this video is the highlight of my quarantine

  • @evie5375
    @evie5375 Před 3 lety

    dude, thank you SO much! i was having a hard time with this and this totally helped! bonus points for also actually explaining how and why it works the way it does!

  • @yaaahoo2126
    @yaaahoo2126 Před 5 lety +2

    5:36 why is it -5 and how do you know when to make it -

  • @JuanRodriguez-fe1ss
    @JuanRodriguez-fe1ss Před 6 lety +2

    Thanks for sharing your knowledge.

  • @randombrilliance5921
    @randombrilliance5921 Před 3 lety

    Thanks, You saved my life. Got yourself a new sub

  • @Randomalistic
    @Randomalistic Před 6 lety +2

    Thank you!! Got straight to the point and was very informative :)

  • @hetvikhetia4354
    @hetvikhetia4354 Před 6 lety +2

    This is very helpful and easy to understand.

  • @aminaali857
    @aminaali857 Před 5 lety +2

    Your video really helped me I appreciate it thanks 🙏

  • @tylerhubley2450
    @tylerhubley2450 Před 6 lety +2

    Amazing job man you did a great job and helped me a lot

  • @simoncolligan3944
    @simoncolligan3944 Před 4 lety

    Thanks - very useful -- normally that '25' that you put in is put in as a fraction over 2, then brackets which are squared ... exactly the same thing, but o much more confusing when you don't really realise what's happening to/with that extra equation - this made it crystal clear :)

  • @matblacc6418
    @matblacc6418 Před 3 lety

    Thank you im in 8th grade and learning algebra my teacher doesn't explain it like you do.

  • @user-yj8ek2ox7s
    @user-yj8ek2ox7s Před rokem

    Thanks for making the concept clear! You're a great teacher..

  • @Peanutbutterjellytime231

    I'm looking at the comments in a bunch of videos and all these people seem like they are in a higher grade than me doing what I'm doing. I'm in 8th grade? What? I'm home schooled but someone pls answer my question. Why is this happening to me. Okay I'm done (btw u r better than my teacher)

  • @edwinmariano5131
    @edwinmariano5131 Před 4 lety

    The actual process is divide all terms by the coefficient of the x^2 before proceeding to the process explained.

  • @januszjasniowski8890
    @januszjasniowski8890 Před 3 lety +1

    Można także to równanie kwadratowe rozwiązać przy pomocy delty .

  • @kellymulderino7156
    @kellymulderino7156 Před rokem +2

    where was youtube when i was in highschool in the 80s

  • @sandiknits4174
    @sandiknits4174 Před 3 lety

    This really IS the best explanation!!

  • @avischiffmann6220
    @avischiffmann6220 Před 4 lety

    watched so many videos, this is the one that made me finally get it so thank you!

  • @bsn1-1antoniokarlabrahamxe30

    u are definitely surely amazingly better than my prof hat on you

  • @ballad
    @ballad Před 3 lety

    lol my teacher explained the exact same thing but i only understood this one for some reason xD. Thanks this was helpful.

  • @contemporarilyancient
    @contemporarilyancient Před 2 lety

    We could further simplify it as
    -5 ± sqrt16 × sqrt2
    -5 ± 4sqrt2

  • @lovelydream6924
    @lovelydream6924 Před 5 lety +1

    Doesnt radical 32 simplify in 4radical2

  • @GWAIHIRKV
    @GWAIHIRKV Před 4 lety

    That is the best explanation I have seen. Thanks.

  • @hyunjunewon5629
    @hyunjunewon5629 Před 4 lety

    Why does 1/2 of the coefficient of x suddenly come into the equation? What role does it play in it?

  • @sustone6772
    @sustone6772 Před 4 lety

    Is that right answer ? Can 32 square root become 16*2

  • @eranocampos8783
    @eranocampos8783 Před 3 lety

    Im from the Philippines
    Good explanation bro

  • @KuhDeeee
    @KuhDeeee Před 5 lety +1

    Great vid man, really helped me out can you do more?

  • @ottoomen5076
    @ottoomen5076 Před 5 lety +2

    Someone else needs a math channel called "In plane english"

  • @dankrecordz7954
    @dankrecordz7954 Před 6 lety +1

    This was Extremely helpful! thanks a ton!

  • @samstan4462
    @samstan4462 Před 4 lety

    My mind just got a workout! Well explained.

  • @piusdebankz1317
    @piusdebankz1317 Před 5 lety

    if the coefficient of x is -10, will you still add +25 to both sides or will you will you apply -25 instead. i am refering to an equation that looks like this x^2-10x-7=0 ??? Thank you

  • @salemsolomon57
    @salemsolomon57 Před 5 lety

    Literally the best explanation

  • @krishaangd
    @krishaangd Před 4 lety +1

    But what if it isn’t 10x say it’s 13x or 17x

  • @pewpewwepwep9296
    @pewpewwepwep9296 Před 6 lety +1

    Actually better than my prof😂😂

  • @naheeroine
    @naheeroine Před 4 lety

    Awesome Explanation!!! Thank you so much 🙏

  • @mostafaehab7302
    @mostafaehab7302 Před 5 lety +1

    Best explanation ever♥️

  • @CasaErwin
    @CasaErwin Před 6 lety

    For a demo, why didn't you start with x^2 + 10x - 11 = 0 ? That way, after completing the square, you get a perfect square on each side.

  • @NewCandownFarm
    @NewCandownFarm Před 10 měsíci

    Acellus needs to hire you. My daughter is so frustrated with math. Im so frustrated with my attempts to help her. Would you be upset it i wrote/spoke with the school about you?

  • @ryanhendrymusic
    @ryanhendrymusic Před 6 lety +1

    Title is accurate. Thumbs up

  • @safaa5294
    @safaa5294 Před 5 lety +1

    this was very helpful ^.^

  • @TaggingTechnician
    @TaggingTechnician Před 6 lety

    Well done, clear process and clear easy to follow notes.

  • @michawu4401
    @michawu4401 Před 4 lety

    Leaving sqr32 in math tests is unacceptable in my country. Should be sqr 16*2 = 4 sqr2.
    BTW.
    This quadratic equation might be figured way easily:
    1/ Delta = b^2 - 4ac = 128
    2/ sqr 128 = 4 sqr8
    3/ x1 = -5 - 2 sqr8
    X2 = -5 + 2 sqr8
    Eot

  • @robertbrandywine
    @robertbrandywine Před 6 lety

    What does solving a quadratic equation have to do with the real word? How would we get to the point where something physical was described by a quadratic equation?

    • @calebsmith1660
      @calebsmith1660 Před 5 lety

      Robert Brandywine You can apply it to some physics problems which have to do with real world situations.

  • @iankingon
    @iankingon Před 5 lety +1

    you sir, are a GOD

  • @curtlumbo5640
    @curtlumbo5640 Před 5 lety

    better than our math teacher

  • @maritescadiz8141
    @maritescadiz8141 Před 3 lety

    It make sense thanks for sharing your ideas.

  • @aeyaacosta
    @aeyaacosta Před 6 lety +1

    sir, the square root of 32 can be simplified further, right?

    • @mathaha2922
      @mathaha2922 Před 5 lety +1

      Yes: sqrt(32)=sqrt(16*2)=sqrt(16)*sqrt(2)=4*sqrt(2). He probably left out the simplification so as not to distract from the main point of the video, but you make a good point.

    • @collinceobedo
      @collinceobedo Před 5 lety +1

      He didn't work out the square root of 32 to avoid confusing the amateurs