Solving linear systems by substitution | Algebra Basics | Khan Academy

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  • Опубликовано: 8 янв 2025

Комментарии • 667

  • @pookiesamurai7500
    @pookiesamurai7500 9 лет назад +692

    this short video explained more than 45 minutes of rushed class time , thank you khan~

    • @cat_jk00
      @cat_jk00 8 лет назад +60

      Yeah, the problem with a lot of math teachers is the fact that they have been good at math for their entire life, and they can't see that some people aren't. Great teachers had to work to become great, and other's didn't.

    • @pookiesamurai7500
      @pookiesamurai7500 8 лет назад +7

      Exactly.

    • @nooneliveshere9303
      @nooneliveshere9303 5 лет назад

      Thank you khanye very cool

    • @tati.5664
      @tati.5664 5 лет назад

      right!

    • @abendeavours4200
      @abendeavours4200 5 лет назад +2

      Sal*

  • @shirokatsumi364
    @shirokatsumi364 5 лет назад +267

    This was easy than I thought. I only learned for 5 mins by watching this video, while 3 hours of our teacher teaching us math while rapping very fast

  • @mcmiller1537
    @mcmiller1537 8 лет назад +1131

    Khan academy is literally the only way I understand math.

    • @Grayman2003
      @Grayman2003 8 лет назад +2

      MC Miller Same. Lol

    • @Unluckyleon
      @Unluckyleon 8 лет назад +9

      MC Miller I'm have a. Test tomorrow and I'm doing last moment khan academy revision XD

    • @minkihairoil
      @minkihairoil 7 лет назад +1

      Lol I don't get it styll

    • @suavefrog5029
      @suavefrog5029 7 лет назад +3

      They teach me better than most of my math teachers 😄

    • @mepe705
      @mepe705 6 лет назад +1

      Mc miller same I’m literally watching this before I need to go to school and I have a test

  • @atishayajain5073
    @atishayajain5073 3 года назад +118

    I despise online school, I suffer from adhd and I can barely concentrate in my home environment compared to my school environment. My grades went from As and Bs to Cs and Ds and i almost failed 1 course not to mention that I am now 5% from failing math. This man is helping a lot during pandemic. Even if some of his videos were made over 10 years ago.

  • @priscilaherrera6640
    @priscilaherrera6640 8 лет назад +262

    This is so unbelievably helpful 😭 I'm crying because his 2 in the morning and I've been stuck in this homework for the past hour and it took me only 2 minutes to understand with him.

    • @blxzing1201
      @blxzing1201 8 лет назад +3

      Omg same

    • @mxlky9187
      @mxlky9187 8 лет назад +1

      Me right now

    • @andrewgarcia188
      @andrewgarcia188 6 лет назад +3

      sadly yes not knowing what to do no progress more than three hours with it being after midnight
      made me depressed and I broke
      luckily this guy can teach

    • @yemixakin
      @yemixakin 5 лет назад +1

      Ogeyand

  • @michelleelliott4402
    @michelleelliott4402 9 лет назад +443

    this makes so much sense now. why can't my math teacher do this

    • @nytrowgen2889
      @nytrowgen2889 9 лет назад +5

      +michelle elliott mine too

    • @JeffnasticsPvP
      @JeffnasticsPvP 9 лет назад +3

      +michelle elliott SAME

    • @Hello-cs2bv
      @Hello-cs2bv 8 лет назад +5

      +michelle elliott It's like the teachers know this, but they suck at teaching and because of that, they have to help other students and the teacher doesn't have time to help you.

    • @jimkeller3868
      @jimkeller3868 8 лет назад +17

      +michelle elliott I think most teachers DO teach it exactly this way, and this clearly. There are 3 things I believe most people don't consider when thinking this is somehow a clearer explanation: 1) you're in a completely different setting. At home, relaxed, later in the day so perhaps more awake.
      2) You can stop the video and replay it or you can stop it and think about it. You can't stop the flow of time in your classroom. In this respect, there is less pressure. 3) you are learning alone. There is no peer pressure, the feeling of embarrassment if I ask a dumb question. There are less distractions and concerns about other students or your teacher.
      The above content is not four-dimensional tensor calculus. It is straight forward and fairly easy to teach.

    • @Cluetube
      @Cluetube 8 лет назад +1

      +Jim Keller i actually kinda agree with Jim.
      but at the same time
      i kinda dont.
      but since i cant really put my reasons why i cant into word form.
      ill just leave it at JIMS RIGHT.

  • @Jessicanimation
    @Jessicanimation 3 года назад +100

    10 years later and I'm relying on this channel for basic algebra.

  • @abhithegod1046
    @abhithegod1046 4 года назад +56

    time:1 hour to algebra test
    teacher:you guys have 1 hour to finalize your studying
    me : i need 9:20 minutes only

  • @boislaya9810
    @boislaya9810 5 лет назад +42

    Soooooo khan for president or what? I never have wanted to thank someone more, Thank you!

  • @derrickhess928
    @derrickhess928 10 лет назад +323

    Without khan academy I would be failing algebra

  • @Mar-om6ct
    @Mar-om6ct 6 лет назад +93

    the traditional school system is soo old and makes things so hard, and the teachers only explain once and expect us to know everything, but every student has different needs

    • @Mar-om6ct
      @Mar-om6ct 3 года назад

      @Anime Watcher 🖥 🍿 replying after two years 😂

    • @Mar-om6ct
      @Mar-om6ct 3 года назад

      @Anime Watcher 🖥 🍿 replying just after I wake up 😂

    • @AshmewStudios
      @AshmewStudios 3 года назад

      @@Mar-om6ct nice

    • @Mar-om6ct
      @Mar-om6ct 3 года назад

      @@AshmewStudios early reply

    • @AshmewStudios
      @AshmewStudios 3 года назад

      @@Mar-om6ct good job

  • @nickyy.333
    @nickyy.333 3 года назад +24

    I've been struggling in my math class for many days trying to understand and this helped me understand it so quickly. Thank you!! 😭

    • @minimage1055
      @minimage1055 3 года назад

      Are you in 9th grade?

    • @KNGallen
      @KNGallen 2 года назад

      @@minimage1055 grade 10 academic 😭

    • @minimage1055
      @minimage1055 2 года назад

      @@KNGallen I’m going to grade ten next year, how is it? Ac math

    • @KNGallen
      @KNGallen 2 года назад +1

      @@minimage1055 it’s definitely challenging but I’m finding it so far much easier than grade 9. Might just be my teacher who made it so hard in grade 9 but if you stay on top of homework you should be fine.

    • @minimage1055
      @minimage1055 2 года назад

      @@KNGallen thank you so much, I’m really good in school I just have so much anxiety haha

  • @ezthelegendary8441
    @ezthelegendary8441 5 лет назад +8

    i hope this guy goes straight to heaven. he helped me through middle school school and still helping me in high school. thank you khan

  • @sashaanand8714
    @sashaanand8714 11 лет назад +12

    Thank you so much. This video has saved my life!!! I was absent from school today and our homework was on this topic. When I tried do do it I was lost. Thanks to this video I now understand it. Way easier than I thought!!!! Thanks again, Khan Academy!!!!😀

    • @nebulai9587
      @nebulai9587 5 лет назад +2

      You're welcome. Even 5 years ago

    • @Ryan-sm5sw
      @Ryan-sm5sw 3 года назад

      Hows the adult life bro

    • @smajerboy25
      @smajerboy25 2 года назад

      @@Ryan-sm5sw maybe not so good o.o

  • @jayhawkkgames3434
    @jayhawkkgames3434 8 лет назад +57

    Learned more in a minute of watching than 50 minutes of pre algebra tbh

  • @Kingzach01
    @Kingzach01 8 лет назад +25

    Thank you Khan Academy for helping me not fail algebra. 👍👍👍.

  • @yourneighborhoodana4584
    @yourneighborhoodana4584 3 года назад +5

    Thank you so much. In fifth grade my teacher was teaching my class 7th grade math and I would have failed if not for you. So far in eighth grade these videos are helping as well!

  • @matthewawaldrep
    @matthewawaldrep 11 лет назад +38

    This video is pure gold.

  • @sarahlusignan4751
    @sarahlusignan4751 4 года назад +7

    I was struggling so hard on this in class, but 2 minutes into the video and i already understand. THANK YOU!!!!

    • @Lizzygaming101
      @Lizzygaming101 4 года назад +1

      Can you help me with an equation and explain to me how it works bc I'm still confused bc either way if you put the x or y on the side of the equation by itself it still has a number in front of it and I don't understand

  • @dark_fury1595
    @dark_fury1595 Год назад +1

    khan academy helped me with my understanding of math, the way my teachers explains things confuses me meanwhile, khan academy actually explains and goes directly to the point, please donate to them so they can help students like me understand and learn math

  • @Spacey75257
    @Spacey75257 6 лет назад +4

    I have a review packet in 8th grade for things from 7th grade, but some are new that we’ve never done before, and some are too complicated to remember over summer, so this is a lifesaver

  • @tejassraveendran9370
    @tejassraveendran9370 5 лет назад +7

    I got a 91 in my Math Exam with he help of this video, thank you!

  • @shinigami-scythe5874
    @shinigami-scythe5874 9 лет назад +4

    omll thank you so much im currently in the process of doing homework over winter break (long story) and since the teacher isnt here this helped so much thank youuu :DD

  • @askaksa6385
    @askaksa6385 6 лет назад +2

    I don't know if the people from khan academy know that they are actual gods that have saved so many of us. From the bottom of my heart, thank you.

  • @PrimeQualitySports
    @PrimeQualitySports 3 года назад +2

    That's one great explanation. No steps were missed and each step was explained. Some teachers skip explaining certain steps assuming that the student already knows about it but they don't.

  • @mariammozham5533
    @mariammozham5533 10 лет назад +89

    I still dont get and I have a test and monday.I hate math

    • @GrubworldLinearMusicChannel
      @GrubworldLinearMusicChannel 9 лет назад +8

      +Mariam Mozham Khan Academy is making me solve it easier than my math teacher..

    • @chrisandboyz77
      @chrisandboyz77 7 лет назад +1

      Mariam Mozham me too

    • @ryll5277
      @ryll5277 7 лет назад

      they problemly got you confused by them subracting by 2y on both sides, but relly its easier to solve by subtracting x on both sides then get y alone by dividing the 2 by -x+9

    • @deletedchannel2659
      @deletedchannel2659 6 лет назад

      Mariam Mozham me too... i still don’t get it

    • @jayfml2243
      @jayfml2243 5 лет назад

      what'd you get on the test on monday?

  • @rauldanted9652
    @rauldanted9652 7 лет назад +2

    Life saver, my teacher can't barely explain clearly, your awesome

  • @HP-fj2mi
    @HP-fj2mi 6 лет назад +6

    Great explanation! I'm glad I was able to find this video.

  • @beatrizvaldes2839
    @beatrizvaldes2839 8 лет назад +100

    it's 2 in the morning and I'm studying last minute for a test I have first period...

  • @sk8rmonkeys91
    @sk8rmonkeys91 11 лет назад +1

    dude!! thank you!!! i spent an hour staring at my book and going through useless vids, but yours is dope!! you earn my subscription!!! i hope you find money on the street as you walk.

  • @sakuyaizayoi9876
    @sakuyaizayoi9876 5 лет назад +5

    My teacher Mr.Richards recommended me here, because I had a F, but he knew I was trying. This helped mate! (There is multiple Richard's in the world so I didn't censor it)

  • @ZavryNelson
    @ZavryNelson 4 года назад +8

    this man I found on the internet taught more than my actual math teacher...

  • @penguiz23
    @penguiz23 10 лет назад +4

    Thanks, my math teacher taught us a method that made absolutely no sense at all; this helped a lot- thanks this saved me.

  • @cat_jk00
    @cat_jk00 8 лет назад +2

    Sal's a bad ass wizard man who conjures the simplest thing ever out of thin air. Magic.

  • @IvanThaTerrible99
    @IvanThaTerrible99 11 лет назад +3

    this really helped me alot in algebra. Khan is a genius.

  • @silvershi414
    @silvershi414 4 года назад +4

    bruh he sounds so excited his energy really makes me want to learn

  • @vedarthkondapally6042
    @vedarthkondapally6042 7 лет назад +1

    LETSSSSSSSSSSSSSSSS GOOOOOO I LEARN MORE FROM 4 MINUTES OF THIS THEN I EVER HAVE IN SCHOOL!!!!!!!!!!!!!!!!!!!!

  • @MehkaiManzano
    @MehkaiManzano 4 года назад +1

    khan academy is the hero we need during quarantine, but not the hero we deserve

  • @ilikepizza2020
    @ilikepizza2020 6 лет назад +10

    I have my state exams tomorrow, and I have to pass in order to receive a high school diploma. I'm quite nervous, so I'm reviewing. Thanks for this video!

    • @maverick885
      @maverick885 5 лет назад +4

      Did you pass?

    • @iceaspect7591
      @iceaspect7591 5 лет назад +3

      @@maverick885 bro i was wondering the same

    • @manicpixie8672
      @manicpixie8672 4 года назад +1

      Did you

    • @ilikepizza2020
      @ilikepizza2020 4 года назад +5

      Evelyn McNaughton yes, I did pass! I’m graduating this year!

    • @ilikepizza2020
      @ilikepizza2020 4 года назад +4

      Ya boy Mav yes, I did. Sorry for the late reply.

  • @abrahamsolorio7906
    @abrahamsolorio7906 7 лет назад +38

    HOW TF IS THIS GONNA HELP ME IN LIFE

    • @seb7202
      @seb7202 7 лет назад +23

      Math is the language through which you understand physics, and physics is the study of how this physical world moves and behaves. By extension, since physics shows how objects in motion behave, it also has many applications in every other kind of science. So if you want to work in a stem field, be a doctor, a vet, and hell a sniper for the military, you need a solid math background. There are also many other jobs in finance and business that require basic to advanced mathematics. Not only that but our everyday lives are heavily impacted by discoveries in stem, technology is typically the lens through which we see the world (for example engineering and technology which is heavily math based influences how well doctors can see your cells ie microscopes thus mathematics has saved your life by allowing advancements in the medical field with this new knowledge of cells). So really how has it not already helped you?
      tl,dr
      unless you want it to, it won’t.

    • @matthewwurster1133
      @matthewwurster1133 6 лет назад

      Nice explanation

    • @luidnathan5311
      @luidnathan5311 6 лет назад +2

      @@seb7202 Good one.

    • @abdalrhmansalman7225
      @abdalrhmansalman7225 5 лет назад +1

      It wont :)
      This is the schooling system

    • @manicpixie8672
      @manicpixie8672 4 года назад +2

      We'll say life has ten apples ......

  • @BehindYouSir
    @BehindYouSir 10 лет назад +3

    Thank you so much. At first I was having trouble in my class, but this video cleared it up excellently! Thanks again!

  • @lasagna8964
    @lasagna8964 3 года назад +2

    Oh my god I actually get it now! I’ve been trying for like a week but EnVision math isn’t any good. Thank you, Sal Khan

  • @pumpkinlover2102
    @pumpkinlover2102 8 лет назад +2

    honest to god just studied for my math provincial just from watching these videos, learned way more than a full semester of math class

  • @Seattle206723
    @Seattle206723 14 лет назад +3

    Very useful, and displayed. Wish you were my math instructor. Well you are, shall we say. Thanks again

  • @tinayang5750
    @tinayang5750 3 года назад

    Literally, my math class is like an hour and 25 min, and I did not get what the teacher was saying, thank you sooooo much that now I know how to use this method!!

  • @Mero-lz9bo
    @Mero-lz9bo 2 года назад +2

    ALLAhuAkbar BISSSMALAHAH, Sal Khan, may ALLAh bless you, habibi

  • @akashrahman6169
    @akashrahman6169 10 лет назад +3

    at last, i found some kinda math that im talking about..... thanks khan, it helped me a lot.... all the other videos were just an easy exapmle of how to do linear.......(bla bla bla) but this one actually helped me

  • @maddielentz3777
    @maddielentz3777 5 лет назад +8

    you’ve thought me more my 8th grade math year then my actual teacher ever could have

  • @drludbA
    @drludbA 2 года назад +3

    Khan Academy in 10 minutes > 11 hours of class time

  • @_alphasierra4705
    @_alphasierra4705 8 лет назад +1

    Much much clearer than how all the others i have seen on youtube teach about it

  • @brookebobbitt8061
    @brookebobbitt8061 5 лет назад +1

    Oh thank god I found this, I have a test tomorrow and I was full on panicking but now I understand how it works!!

  • @BEASTLEGEND21
    @BEASTLEGEND21 9 месяцев назад

    i have been struggling with the subsitution method and now i understand it . THANKS KHAN

  • @nenecoulibaly549
    @nenecoulibaly549 5 лет назад

    Sal Khan is a good man. Thank God for Khan Academy.

  • @EmmyKhan
    @EmmyKhan 9 лет назад +2

    and whoa, this just helped me understand it all instantly when it comes to the substitution method. Thanks from Sweden =)

  • @antoniaorduno2396
    @antoniaorduno2396 3 года назад +1

    Love your videos . You explain it so much Better . God bless you . 🙂🙏

  • @BigMan10847
    @BigMan10847 Год назад

    Thank you. I was stuck on a problem for a solid 25 minutes this helped me solve it

  • @new-gacha-riddles-jp
    @new-gacha-riddles-jp 2 года назад

    Thanks, you explained a 1-hour long math lesson in less than 10 minutes.

  • @imswiiftz730
    @imswiiftz730 8 лет назад +3

    Khan Academy
    My teacher sucks she is so bad doesn't even care/help this helps she rushes in the 50 mins of. Class
    I hope this helps me for my quiz tomorrow on this
    Thanks KHAN

    • @heylosersaykidbackwards9021
      @heylosersaykidbackwards9021 8 лет назад +1

      my teacher doesn't suck but shes AWEFUL at teaching students. she talks way to fast and writes really fast and at the same time you also have to be ready to answer any questions that she throws at you in the middle of the class during the notes. HIGH SCHOOL IS TOUGH :(

    • @TacoMastersAssociation
      @TacoMastersAssociation 8 лет назад +1

      I have to retake a quiz now because I was absolutely stumped. I wish I discovered this earlier on, though. High School sucks.

  • @ghassanalbabili2407
    @ghassanalbabili2407 6 лет назад +1

    THANKS KHAN ACADEMY .BEST MATH TEACHER

  • @TLZ1717
    @TLZ1717 4 года назад +1

    This video makes this concept so much easier to understand. I am amazed :)

  • @Abel_la_Abel
    @Abel_la_Abel 9 лет назад +1

    That's amazing, creating numbers from just thin air (almost). I found Thai very helpful especially since I'm studying for sats

  • @ballisticpug6764
    @ballisticpug6764 3 года назад +1

    Watched this mid test while on Zoom. Thanks so much

  • @sebs5027
    @sebs5027 Год назад

    BRO YOU SAVED MY LIFE, THANK YOU SO MUCH, you explained this better in 10 minutes than my teacher could in 2 weeks

  • @fozanhaider1407
    @fozanhaider1407 8 лет назад

    this is amazing I learned this in under 5 min rather then my tutor in a hour thanks^^^

  • @Jiraiya27
    @Jiraiya27 2 года назад +1

    Thanks a lot hope this video get more likes

  • @drludbA
    @drludbA 2 года назад +2

    Khan Academy is goated

  • @Nicky_gzb
    @Nicky_gzb 9 лет назад +1

    Omg thank you sooooo much I didnt understand when my teacher was teaching and then I watched this video and I still didn't understand till I watched it again step by step and now I got it so thank you so such

  • @bashirgagigi172
    @bashirgagigi172 9 лет назад +4

    Thank you very much really appreciate your great and unique work

  • @teresa3861
    @teresa3861 12 лет назад +1

    I learned from this video (,: Finally, RUclips has a purpose!

  • @Izzyhiphop147
    @Izzyhiphop147 13 лет назад +6

    @gointosleep Mr Khan : uses his head
    Teachers : Uses teacher book

  • @FiierceGaaming
    @FiierceGaaming 12 лет назад +2

    i love how my teacher explains this for weeks and i dont get it, then i watch this and understand perfectly

  • @sugar2370
    @sugar2370 11 лет назад

    This was actually really helpful. Better than all the other videos I've tried. I understand perfectly.

  • @hongrand
    @hongrand 9 лет назад +3

    Khan Academy is God's sent angel.

    • @jayfml2243
      @jayfml2243 5 лет назад

      Philip Birgenheir is our God. Join our community and subscribe to him

  • @sagittariusbeauty
    @sagittariusbeauty 3 года назад +1

    Thank you for explaining this 🙏

  • @Miranda_Writes
    @Miranda_Writes 7 лет назад +1

    Wish my instructor made it this easy. Thank you.

  • @htorbecerra
    @htorbecerra 13 лет назад +4

    love how this is taught

  • @xler12
    @xler12 13 лет назад +1

    you're a better teacher than my math teacher in school xD at least you could explain how these things are done unlike my teacher

  • @williamnefalar858
    @williamnefalar858 3 года назад +1

    His voice is so understandable

  • @desanovinarts
    @desanovinarts 3 года назад +1

    Wait so can you do either variable in the top equation to start? Also is both have a number next to them does that change anything?

  • @sleepyidot
    @sleepyidot 4 года назад +1

    10 years later and this guy is still the reason im passing algebra

  • @AircrewAcademy
    @AircrewAcademy 3 месяца назад

    You are a life saver Sal. Allah bless you. ❤

  • @jensonee
    @jensonee 5 месяцев назад

    you're breaking my brain!! thanks.

  • @brandynblehm2937
    @brandynblehm2937 10 лет назад

    This explained it better than my algebra teacher, Thanks! I subscribed to you.

  • @eminso2102
    @eminso2102 3 года назад

    Wow legit can learned anything from these videos, thanks!

  • @brandon-sr4ld
    @brandon-sr4ld 5 лет назад

    khan academy is the reason i have an a in math, thank u so much man

  • @a_smiling_gamer9063
    @a_smiling_gamer9063 Месяц назад

    8:44 Apparently this solution also works
    70 - 11
    59 / 2 = 29.5
    29.5 + 11 = 40.5
    Quick check: 40.5 + 29.5 = 70
    Version with variables is better but if you want to understand a different solution then here you go

  • @evelynmao2909
    @evelynmao2909 9 лет назад +19

    how are you so smart im an idiot at this

  • @deoferiopatrickdaniel16
    @deoferiopatrickdaniel16 4 года назад

    This guy teach very well and easy to understand

  • @eel7349
    @eel7349 3 года назад

    During the pandemic we have half of our classes online and the 2 days I had in class to ask for help in math we’re cancelled and the test is Monday, thanks for these vids

  • @simplystrawb
    @simplystrawb 7 лет назад +1

    This literally helped so much and saved so much more of my time so thank you

  • @Gammer-xd3bh
    @Gammer-xd3bh 5 лет назад

    BRO THE BEST way I learn is Khan Academy FR!

  • @spencercavan8745
    @spencercavan8745 5 лет назад +4

    how do you know when you can multiply by -1 to make the 7 positive, would -7 be wrong?

    • @ayelelleososole4588
      @ayelelleososole4588 2 года назад

      Kind of, the y can’t be negative. That’s why you multiply it by -1.

  • @hany7990
    @hany7990 7 лет назад +1

    YOI EXPLAIN BETTER THAN MY TEACHER!!!! THANKS FOR HELPING!

  • @Wingx0
    @Wingx0 11 лет назад +1

    Khan Academy: thoroughly explains everything and WHY you do it.
    My math teacher: Don't do this, it won't work.

  • @pbjexell
    @pbjexell 2 года назад

    Why does this man explain this better than my math teacher?

  • @rehmanahmed7466
    @rehmanahmed7466 3 года назад

    Thanks a lot khan academy, now i can actually do my home work 😊

  • @trusei
    @trusei 3 года назад +1

    thank you now i can go to the exam

  • @georgedavistube
    @georgedavistube 6 лет назад

    you are a very clear and understanding teacher, I love your videos

  • @harrietiscoolll
    @harrietiscoolll 4 года назад +3

    my brain is slowley entering an endless paradox of confusion and pain

  • @luidnathan5311
    @luidnathan5311 6 лет назад

    Thank you Khan Academy, you are the reason math is very easy.