Two-variable linear equations and their graphs | Algebra I | Khan Academy

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  • เผยแพร่เมื่อ 8 ก.พ. 2025
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    Introduction to 2-variable linear equations and their graphs
    Algebra I on Khan Academy: Algebra is the language through which we describe patterns. Think of it as a shorthand, of sorts. As opposed to having to do something over and over again, algebra gives you a simple way to express that repetitive process. It's also seen as a "gatekeeper" subject. Once you achieve an understanding of algebra, the higher-level math subjects become accessible to you. Without it, it's impossible to move forward. It's used by people with lots of different jobs, like carpentry, engineering, and fashion design. In these tutorials, we'll cover a lot of ground. Some of the topics include linear equations, linear inequalities, linear functions, systems of equations, factoring expressions, quadratic expressions, exponents, functions, and ratios.
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ความคิดเห็น • 261

  • @jackhrovat4172
    @jackhrovat4172 7 ปีที่แล้ว +160

    My teacher explained this in class and I literally was lost but this video saved me. Thank you Sal Khan you are a miracle to this madness

  • @savagegaming5024
    @savagegaming5024 6 ปีที่แล้ว +563

    am I the only one who wonders how he writes perfectly with his mouse

    • @erebosgodofdarkness9708
      @erebosgodofdarkness9708 6 ปีที่แล้ว +34

      i was wondering that to it probably a smart pad though that has a pen probably the reason why its so neat

    • @Planktonbrained
      @Planktonbrained 6 ปีที่แล้ว +26

      He probably has a drawing tablet he just uses it for teaching instead lmao

    • @samuelpaul5091
      @samuelpaul5091 5 ปีที่แล้ว +2

      There is a thing known as specktron check it out

    • @sweetberries4611
      @sweetberries4611 5 ปีที่แล้ว +1

      he is using drawing/wacom tablet

    • @JAMISONFAWKES13
      @JAMISONFAWKES13 5 ปีที่แล้ว +3

      He turned up the stability

  • @ciaras.tishereandilikepota8519
    @ciaras.tishereandilikepota8519 5 ปีที่แล้ว +283

    Time goes so fast when you're trying to figure out how to do your homework😭

  • @TheWheelchairGuy
    @TheWheelchairGuy 9 ปีที่แล้ว +78

    Thank you Sal. My teacher explained this in 3 hours and I didn't get it, but you explained in less that 9 minutes and I got the whole idea. You're the best

    • @thomasjohnsoniibuitizon6973
      @thomasjohnsoniibuitizon6973 9 ปีที่แล้ว +2

      +Mo bahjat i agree, i don't know why i don't understand a single thing to my prof said when she's discussing, but i do understand them when i watched how it works in youtube

    • @TheWheelchairGuy
      @TheWheelchairGuy 9 ปีที่แล้ว +7

      +Silent Walker some teachers don't make sense at all

    • @tekshiibangtanandistan7seo793
      @tekshiibangtanandistan7seo793 7 ปีที่แล้ว +2

      Mo Bahjat true

    • @erebosgodofdarkness9708
      @erebosgodofdarkness9708 6 ปีที่แล้ว +1

      my teacher talks way to fast doesnt do it more then once so im stuck in summer school cause she doesnt know how to teach i watch this and it make like 200 times more scene then my teacher just said thats just sad

  • @Wilfred921
    @Wilfred921 7 ปีที่แล้ว +26

    You have a very nice voice, and your instructions are clear! You sound like the smartass brother I never had.

  • @vxnom027
    @vxnom027 ปีที่แล้ว +2

    Thanks so much for this i literally didn't understand my teacher you are a livesaver 👍👍

  • @Veehead1
    @Veehead1 4 หลายเดือนก่อน +2

    His voice is making this fun to learn

  • @stellar7933
    @stellar7933 4 ปีที่แล้ว +14

    Not gonna lie this section of algebra and geometry is like, super fun to learn and is interesting

  • @KmacInTheHouse
    @KmacInTheHouse 9 ปีที่แล้ว +103

    18,000 people and no one has said "first" yet. Wow.

  • @wanda7927
    @wanda7927 6 ปีที่แล้ว +153

    Who’s here because of finals

    • @mercury7466
      @mercury7466 6 ปีที่แล้ว +9

      Mid terms

    • @plumberjiminc1
      @plumberjiminc1 6 ปีที่แล้ว +1

      Nico my channel same

    • @joey5818
      @joey5818 6 ปีที่แล้ว

      Have a test on this today along with my premed test

    • @samplays4671
      @samplays4671 5 ปีที่แล้ว

      came here for the reports (grade 8)

    • @PyschoMantis-ol5uk
      @PyschoMantis-ol5uk 5 ปีที่แล้ว

      Im here because of mid terms

  • @rynotfound
    @rynotfound 4 ปีที่แล้ว +12

    Why does This sound like magic to me

    • @Ish71716
      @Ish71716 7 หลายเดือนก่อน

      It is indeed magus dear

  • @sonofsam5825
    @sonofsam5825 7 ปีที่แล้ว +3

    This guy always teaches us step by step thanks man

  • @dest1ny690
    @dest1ny690 9 ปีที่แล้ว +11

    3 minutes in and I've learned more in my whole chapter dedicated to this. wow. amazing teaching, thank you Khan Academy.

    • @gojosatoru__
      @gojosatoru__ 7 ปีที่แล้ว

      IKR
      omg i need to stop i have a test

  • @aayush_7037
    @aayush_7037 4 ปีที่แล้ว +1

    I love Khan academy other educational apps or channels are waste

  • @Ad_2030
    @Ad_2030 8 ปีที่แล้ว

    You are the main Khan today!!

  • @valen.08c57
    @valen.08c57 3 ปีที่แล้ว

    my teacher just told my class to watch this video and i'm glad she said that cuz now everything makes so much sense thank you:D

  • @sud7
    @sud7 8 ปีที่แล้ว +7

    Thanks a lot, I was really struggling with my homework!
    You deserve a like!

  • @lizr6099
    @lizr6099 4 ปีที่แล้ว +4

    For the first equation, it looks like the slope would be 2/1. Does this mean that at each point on the pink line, we should count up 2 and over 1?

    • @tturi2
      @tturi2 2 ปีที่แล้ว

      yeah, rise over run

  • @nasidaazhar6534
    @nasidaazhar6534 3 ปีที่แล้ว

    Yes he is a professional when I was at school I didn't understand this concept thanks man you are a great teacher I am subscribing you 😊😊😊

  • @deadlee666
    @deadlee666 4 ปีที่แล้ว +2

    Am i the only who thinks he has an amazing voice ?

  • @brookt6162
    @brookt6162 8 ปีที่แล้ว +1

    Thanks for this video

  • @alexandraperez8583
    @alexandraperez8583 4 ปีที่แล้ว +7

    Am i the only one who found his voice soundlike corpse husband's in 2017? Okay I'm gonna focus now on the lesson

    • @liah8638
      @liah8638 4 ปีที่แล้ว +1

      me too it sounds like corpse lol

  • @r1fl3r93
    @r1fl3r93 3 ปีที่แล้ว

    I think,i can carry on with my studies now,Thanks DUDE 👍👍👍

  • @pinkman6958
    @pinkman6958 9 ปีที่แล้ว +4

    thankz man!!!! i got it

  • @skyb994
    @skyb994 4 ปีที่แล้ว +5

    thank you so muchhhhh I couldn't understand our handouts and i'm already several modules behind. if i just saw this sooner haist. THANK YOU SO MUCHHHHHHHHHHHHHHHHH

  • @reach8157
    @reach8157 4 ปีที่แล้ว +1

    Thanks
    You help me with cyber math 90

  • @selwynmunian3760
    @selwynmunian3760 7 ปีที่แล้ว

    Thank you very much

  • @satchitsb2684
    @satchitsb2684 4 ปีที่แล้ว

    Thank you!

  • @ArielYoursTruly
    @ArielYoursTruly 5 ปีที่แล้ว +33

    Does anybody think there ADD/ADHD affected their attention? Because everytime I was thought something (atleast algebraic), i went to space quicker then the flash.

    • @takemyl478
      @takemyl478 5 ปีที่แล้ว +2

      it does

    • @Jordan-rz3mm
      @Jordan-rz3mm 5 ปีที่แล้ว +3

      Bruh ADD stands for attention deficit disorder.

    • @cloudyjewel766
      @cloudyjewel766 2 หลายเดือนก่อน

      Agreed I don’t know if I have adhd though

  • @tturi2
    @tturi2 2 ปีที่แล้ว +1

    this was so helpful, I forgot how to solve ax-by=c, but you saved me, I tried treating it like a quadratic and factorising but it wouldn't work, it didn't fit into y=mx+c so my head started overheating lol

  • @chawanwitrungroj1353
    @chawanwitrungroj1353 2 ปีที่แล้ว

    Help alot thank

  • @AyaanAhmed12
    @AyaanAhmed12 5 ปีที่แล้ว +4

    Why do the solution of a linear equation in two variable lie in the same line?

    • @SAsquirtle
      @SAsquirtle 5 ปีที่แล้ว +2

      Ayaan Ahmed do you mean why its point of intersection?

    • @shreepadbhat8406
      @shreepadbhat8406 3 ปีที่แล้ว +1

      i think that’s why they are called “ linear “ equations but i still don’t know the reason

    • @AyaanAhmed12
      @AyaanAhmed12 3 ปีที่แล้ว

      I've studied straight lines n now I think, this has to do with slope
      and y=mx+b

  • @yaraligelmarasigan5496
    @yaraligelmarasigan5496 3 ปีที่แล้ว

    okay I had no idea what these lessons mean when I was reading it but now I did because of this guy thank you

  • @piplupofficial8616
    @piplupofficial8616 3 ปีที่แล้ว

    I understood this perfectly in just the first example

  • @fookinlookup5343
    @fookinlookup5343 7 ปีที่แล้ว +4

    2x2 is 4-1=3 khan math

    • @xanderia9850
      @xanderia9850 7 ปีที่แล้ว

      ...am I the only one on the floor dying? K.

    • @Usanemc
      @Usanemc 6 ปีที่แล้ว

      2x2 is 4 - 1 is 3 khan maths :D

  • @angst3990
    @angst3990 6 ปีที่แล้ว +4

    This video really helped me thank you!

  • @jbutler2005
    @jbutler2005 5 ปีที่แล้ว +5

    Thank you Mr. Khan! You are the best!!!👌👏😃

  • @adriandelcampo1312
    @adriandelcampo1312 7 ปีที่แล้ว +5

    1:29 BIG SHAQ QUICK MAFS

    • @tombkings6279
      @tombkings6279 7 ปีที่แล้ว +1

      Adrian del Campo *MATH INTENSIFIES*

    • @jazziemin
      @jazziemin 7 ปีที่แล้ว +1

      Are you a true Asian.

    • @Brett1280
      @Brett1280 7 ปีที่แล้ว +1

      Adrian del Campo hahahah

    • @shikharverma8696
      @shikharverma8696 6 ปีที่แล้ว +1

      boi

  • @Nicola-Lore
    @Nicola-Lore 4 ปีที่แล้ว

    very helpful, thank you !

  • @lesethoysouthh
    @lesethoysouthh 5 ปีที่แล้ว +1

    9 standard is hard...and
    It's the best explanation video I've ever seen
    After 14 days my exams are coming n this guy is making my days easier
    Thank you
    Love from india
    ._.

  • @Planktonbrained
    @Planktonbrained 6 ปีที่แล้ว +1

    You’re a life saver my guy

  • @shikharverma8696
    @shikharverma8696 6 ปีที่แล้ว +2

    i was learning this in school and this is so easy now, thanks khan academy!!!

  • @peejayb7458
    @peejayb7458 9 ปีที่แล้ว +8

    I have a question, when do we actually apply this ?

    • @gojosatoru__
      @gojosatoru__ 7 ปีที่แล้ว +6

      in that test
      yea

    • @xenecro__4453
      @xenecro__4453 6 ปีที่แล้ว +2

      ha ha ha these MAY come in handy in the future, probably not but they MAY thats why they torture us with these assignments

  • @dylan3016
    @dylan3016 7 ปีที่แล้ว

    Very helpful

  • @doxlush7676
    @doxlush7676 8 ปีที่แล้ว +6

    which software is he using

  • @imnotyuan3141
    @imnotyuan3141 4 ปีที่แล้ว +1

    At 5:00, what if they can’t be divided?

  • @jamesjohnston1481
    @jamesjohnston1481 8 ปีที่แล้ว

    thank you

  • @dhankness
    @dhankness 7 ปีที่แล้ว

    I understood it now

  • @ajkyot8727
    @ajkyot8727 5 ปีที่แล้ว +3

    Hey where did x come from pls. Answer ASAP

    • @kitty-et3sd
      @kitty-et3sd 5 ปีที่แล้ว +1

      April Joy Quisto i think you can choose any number for x

    • @joshthio00
      @joshthio00 4 ปีที่แล้ว

      x is a variable, so it is unknown.

    • @jirielrantayo7609
      @jirielrantayo7609 4 ปีที่แล้ว

      @@joshthio00 When you answer to him 6 months ago 😂

  • @johnellisonarmadilloconstr7966
    @johnellisonarmadilloconstr7966 7 หลายเดือนก่อน

    How do you know that’s a negative 3 and not minus 3? And what would be in between 4x and 3y if it were a positive number?

  • @dirtapple8608
    @dirtapple8608 7 ปีที่แล้ว

    Awesome! I'm now 3 grade levels past what I'm learning!

  • @gojosatoru__
    @gojosatoru__ 7 ปีที่แล้ว +8

    In my auto play:
    It's a twentyonepilots crack video
    what is my life

  • @thejeshwarib5038
    @thejeshwarib5038 8 ปีที่แล้ว

    thanks a lot!!!!!!!!!!!!!!!!!!!!

  • @jakeiski
    @jakeiski 4 ปีที่แล้ว +1

    Aaah. I keep finding myself back here at this channel. Love it

  • @jaysondemarco
    @jaysondemarco 4 ปีที่แล้ว

    wish you wrote the word down but thanks its good

  • @naii6102
    @naii6102 4 ปีที่แล้ว

    how did x be equal to one?? in 1:13 ?? please answer me I'm confused..

    • @cyberpunkchloe9
      @cyberpunkchloe9 ปีที่แล้ว

      If x is equal to 1 multiply by 2, then sub to -3 equals to -1
      x y
      (1 -1)
      Why is it 1? he puts 0 first, so 1 and 2, so on and it will make a line.

    • @venkatreddy8329
      @venkatreddy8329 7 วันที่ผ่านมา

      We're assuming x is 1

  • @reychellevargas4251
    @reychellevargas4251 5 ปีที่แล้ว +2

    Where did -1/2 came from?

  • @chikatakami745
    @chikatakami745 6 ปีที่แล้ว

    Can X and Y be Blank? Or you need to put your own number?

  • @StrvberryM0on
    @StrvberryM0on 4 ปีที่แล้ว +2

    But what if y doesn’t equal a whole number, like it equals 4.5 or something

    • @MelbertjrLUZON
      @MelbertjrLUZON 4 ปีที่แล้ว

      You can still graph it. But if it doesn't intersect the line, then the solution is wrong

  • @juliannapacheco5199
    @juliannapacheco5199 6 ปีที่แล้ว +2

    I still dont get how u did the 4x - 3y = 12

    • @juliannapacheco5199
      @juliannapacheco5199 6 ปีที่แล้ว +1

      @neris dwlrma last week, the day i commented that, was midnighr and i didnt sleep at all just to study for the finals/exam/qa but in the end, i was at a mental block. I probably failed the test sighhh

    • @adonisadamn1
      @adonisadamn1 6 ปีที่แล้ว +1

      4x minus 3y equals.to 12
      WE only need to find.the value.of y
      so like if the value of x is 0, 4(0) minus 3 y equals to 12
      0-3y=12 so what is the value.of y that.satisfy that?
      -4 can.satisfy that. equation.because we.need it to.be.the value.of.12 so -3(-4)=12 so its gonna be 12=12

    • @JesterChat81
      @JesterChat81 ปีที่แล้ว

      @@adonisadamn1 This makes no sense.

  • @queenalex6946
    @queenalex6946 8 ปีที่แล้ว +21

    am i the only who thinks you sound like Joe from Family Guy

  • @she7i
    @she7i ปีที่แล้ว

    random question, what microphone do you use?

  • @kevinduliesco5468
    @kevinduliesco5468 3 ปีที่แล้ว +1

    I was confused in a lesson with dots and simple equations and till now I'm still confused

  • @tiantian9434
    @tiantian9434 2 ปีที่แล้ว

    Sir, can we prove that it is linear, or do we hypothesize it is linear? We can't verify every dot, can we?

  • @taeminkookie6710
    @taeminkookie6710 3 ปีที่แล้ว

    How about y>x+2.?

  • @Sondergirl1610
    @Sondergirl1610 6 ปีที่แล้ว +1

    I had a problem with how in heck the equation transferred to a graph coz my teacher didn't explain well enough that I should just randomize "x" and use IT on the actual equation to get "y" on the table . I was instead using substitution and elimination methods whilst never getting my answer

  • @breanagramegna4498
    @breanagramegna4498 7 ปีที่แล้ว

    so since the lines intercept it would be no solution?

  • @asianxhispanic
    @asianxhispanic 4 ปีที่แล้ว +2

    it only took 1 minute and 48 seconds to understand

  • @avlmaster1044
    @avlmaster1044 4 ปีที่แล้ว

    Can someone help becaus ein my book it says the instruction is graph the linear equations in two variables waht will i do will i make a graph or i will sove it?

  • @angelkimtv4061
    @angelkimtv4061 8 ปีที่แล้ว +2

    how do you do pair of equations like this 3x+y=5 and 2x+y=9??

    • @jazziemin
      @jazziemin 7 ปีที่แล้ว

      Pokemon TV TV those equations aren’t linear equations, they are called standard equations. Watch one of their videos to see how to transform one to a Slope.
      Let me show you what it looks like
      Standard form is
      ax+by=c
      Slope form is
      y=mx+b

    • @irshadgoury7223
      @irshadgoury7223 6 ปีที่แล้ว

      vary simple

  • @jhonangellineri7945
    @jhonangellineri7945 5 ปีที่แล้ว

    though may we have variables raised to a negative power? for an instance 3^-8?

  • @kenziethefangirl4838
    @kenziethefangirl4838 5 ปีที่แล้ว

    How come the guy on TH-cam explain this better than my textbook ._.

  • @cosmosms_
    @cosmosms_ 4 ปีที่แล้ว

    he sounds like ranboo wtff 😭😭💜💜

  • @notkacchan560
    @notkacchan560 4 ปีที่แล้ว

    1:30 how did x become 2, the explanation is so confusing, it doesn't say how the number turned into that or anything 🤦‍♂️

    • @dianaaurin5655
      @dianaaurin5655 4 ปีที่แล้ว +2

      Bcuz he's thinking to any number that if you subtract to 3 the answer is 1 so if you think 2×2 is equal to 4 and if u minus it to 3 the answer will be 1 which is the y

    • @chocodesuu
      @chocodesuu 4 ปีที่แล้ว

      @@dianaaurin5655 thanks it helped me out

  • @aha4850
    @aha4850 5 ปีที่แล้ว +1

    I need tp know how he got numbers for x and y,pls help

  • @present8409
    @present8409 5 ปีที่แล้ว

    Thank you Mr. Khan! I got it...

  • @zeke70920
    @zeke70920 3 ปีที่แล้ว

    this is for grade 9 and my teacher is milking the last 2 weeks of school to learn this,
    useless information that i will forget after summer break

    • @-_K.-_
      @-_K.-_ 3 ปีที่แล้ว

      Wait this is for 9th?- then why am I doing this for 8th? 🧍‍♀️

    • @chehalalee867
      @chehalalee867 3 ปีที่แล้ว

      @@-_K.-_ This video is also for 8th graders.

  • @juniormartinez7607
    @juniormartinez7607 3 ปีที่แล้ว

    thank you so much! you really helped me understand thank you.

  • @elle2337
    @elle2337 3 ปีที่แล้ว

    aaaaaa thankyousmmm

  • @duckguy1984
    @duckguy1984 4 ปีที่แล้ว

    how do you make a salary scheme with this method?

  • @zahrahasnawi1123
    @zahrahasnawi1123 8 ปีที่แล้ว

    How do you do equations like y=3 and x=4

  • @ramildelegario9739
    @ramildelegario9739 4 ปีที่แล้ว +1

    Thaks shering vedeo

  • @babysoohwa1510
    @babysoohwa1510 4 ปีที่แล้ว +1

    POV you're stressed out and you search for sumthin because fck

  • @furunet
    @furunet 5 ปีที่แล้ว

    I wish i watched this before the test

  • @mdnisar2107
    @mdnisar2107 7 ปีที่แล้ว

    nice and have a nice day

  • @JBRLETSLEARN
    @JBRLETSLEARN 6 ปีที่แล้ว

    Sir geometrically soon of linear eqn with one variable is a point then why we call it linear eqn

  • @depressodaliato6672
    @depressodaliato6672 ปีที่แล้ว

    From where are you getting random numbers man, i got so confused when u were having x and y in two sections

  • @AdrianMartinez-yk5dd
    @AdrianMartinez-yk5dd 8 ปีที่แล้ว +11

    but how do you do equations that look like 2x+8y=-64

    • @salsYThandle
      @salsYThandle 8 ปีที่แล้ว +1

      solve the equation and the final answer will be 8y= 64-2x

    • @hassanabdul-kareem1882
      @hassanabdul-kareem1882 8 ปีที่แล้ว +5

      don't forget to simplify it. 4y=32-1x -> y= (32-1x)/4

  • @Cheddar101
    @Cheddar101 3 ปีที่แล้ว

    i registered late for a class and started in the middle of a unit im complety lost I hope this helps

  • @ryzennicolee.siguenza917
    @ryzennicolee.siguenza917 4 ปีที่แล้ว

    How did the second graph 3,0 happen???

  • @Randzpery
    @Randzpery 5 ปีที่แล้ว +1

    Can you raise your voice just a little bit please

  • @annie1565
    @annie1565 4 ปีที่แล้ว +2

    *khan academy* 🕳👨🏻‍🦽

  • @sathurn9155
    @sathurn9155 4 ปีที่แล้ว

    What if I get -10, -5, 0, 5, 10? How do I graph that?

  • @breadfactory7634
    @breadfactory7634 4 ปีที่แล้ว +1

    Kaya ayoko sa math eh

  • @aphrodite21gaming17
    @aphrodite21gaming17 4 ปีที่แล้ว

    My teacher asked us to watch this not knowing that I can't understand math clearly

  • @leeianmercado1026
    @leeianmercado1026 6 ปีที่แล้ว +3

    101th!!!!!

  • @jonminchala7368
    @jonminchala7368 4 ปีที่แล้ว

    I still don’t get it bro I need help

  • @WesternRS
    @WesternRS 9 ปีที่แล้ว

    why on the computer .

  • @animeinsider2502
    @animeinsider2502 5 ปีที่แล้ว

    we are gonna generate a _Line_

  • @RonnieWilliams_
    @RonnieWilliams_ 4 ปีที่แล้ว

    first
    i know im 5 years late i just wanna see ppls reactions so dont read this until youve read the replies