Synthetic division example 2 | Polynomial and rational functions | Algebra II | Khan Academy

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  • Опубліковано 31 лип 2012
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    Another example of applying the basic synthetic division algorithm
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КОМЕНТАРІ • 66

  • @erwinjedracho640
    @erwinjedracho640 9 років тому +30

    man..how did they discover this....fuck bro, this isn't math, this is VODOO.....

  • @timmypena241
    @timmypena241 4 роки тому +3

    everybody is doing online classes and my professor posted your video so we can continue our work. I'm glad she did.

  • @danielmak4333
    @danielmak4333 12 років тому +1

    Wow I learned this last semester and totally forgot how to do this. Thanks for the refresher!

  • @kunjankaim6250
    @kunjankaim6250 7 років тому

    Really helped!!! Thanks

  • @Nickadoo500
    @Nickadoo500 6 років тому

    useless stuff, but i got to know it for the next math quiz! thankyou khan!

  • @adamarbab5152
    @adamarbab5152 7 років тому +1

    Now I got it
    thanks!

  • @nii_san1201
    @nii_san1201 6 років тому +2

    i like how he keeps the numbers colored rather than having them in just 1 boring color

  • @MrD3STR03R
    @MrD3STR03R 12 років тому +1

    This is very helpful, Thanks! :D

  • @viet-anhle2440
    @viet-anhle2440 6 років тому +2

    Lol in the first video example he was like in the next example we will show you how it's like voodoo and in this video he says the same thing again😂

  • @biganakan5508
    @biganakan5508 6 років тому +1

    Thank you sooo much !

  • @WhatsBliss
    @WhatsBliss 11 років тому +6

    I actually prefer using synthetic division. I tend to make fewer mistakes and it feels like there's less to keep track of. :P

  • @jayoncetaylor3610
    @jayoncetaylor3610 11 років тому +4

    don't get me wrong, you've done an awesome job explaining how synthetic division is done, I'm just looking for the specific video that you said you that you have explaining why it all makes sense...

    • @rendobro274
      @rendobro274 Рік тому +3

      I got your back bro just search this up "Why synthetic division works | Polynomial and rational functions | Algebra II | Khan Academy"

  • @seajaey1
    @seajaey1 7 років тому +1

    Thanks a lot! 👍

  • @S1rjoemama
    @S1rjoemama 12 років тому +1

    in the last video he says that the degree of the divisor must be 1. In other words in the denominator you can only have (x^1)+ a number

  • @reinowarren7880
    @reinowarren7880 8 років тому +7

    Sal claims that synthetic division works ONLY for x - k as a divisor, NOT SO. It also works for nx - k where the reference value is the solution to nx - k = 0, which is x = k/n.
    There is a slight twist: P(x)/ (nx - k) = P(x)/[n(x - k)] = (1/n)P(x)/(x - k/n). So the quotient of P(x)/(x - k/n) must be multiplied by 1/n (or if you wish, the coefficients must be divided by n).
    Try (8x³ + 2x² + 5x - 6)/(2x - 1): Using the reverence number ½ the original synthetic quotient is 8, 6, 8, with remainder -2. So the real quotient polynomial is 4x² + 3x + 4 and the remainder is -2. That is, (8x³ + 2x² + 5x - 6)/(2x - 1) = (4x² + 3x + 4) + -2/(2x - 1)

    • @investigate711
      @investigate711 6 років тому

      Reino Warren thanks man, it really helps

  • @orizbethsolis3756
    @orizbethsolis3756 3 роки тому +1

    How did you get the [6x to the 3rd power]? It does not make sense? I thought when you dived exponent, you are really subtracting exponents. So, How did you get 6X to the third power?

  • @Sakurachan001
    @Sakurachan001 7 років тому +9

    what if the numerical coefficient of the divisor is 2,3 and so on not 1 . like 2x-3 instead of x-3

    • @udithNRP
      @udithNRP 5 років тому

      then x=3/2! Simple!!

  • @caliconfirmed3984
    @caliconfirmed3984 11 років тому +8

    Forget this, wolfram alpha time -.-

  • @jayoncetaylor3610
    @jayoncetaylor3610 11 років тому +17

    Now... where's the video explaining WHY this all makes sense?

    • @salvadormarley75
      @salvadormarley75 2 роки тому

      you probably dont care but does anybody know a trick to get back into an instagram account?
      I was stupid forgot the account password. I appreciate any assistance you can offer me.

    • @jaxtynallan4195
      @jaxtynallan4195 2 роки тому

      @Salvador Marley Instablaster :)

    • @salvadormarley75
      @salvadormarley75 2 роки тому

      @Jaxtyn Allan thanks so much for your reply. I got to the site on google and im trying it out now.
      Seems to take a while so I will reply here later with my results.

    • @salvadormarley75
      @salvadormarley75 2 роки тому

      @Jaxtyn Allan it worked and I finally got access to my account again. Im so happy:D
      Thanks so much, you saved my account !

    • @jaxtynallan4195
      @jaxtynallan4195 2 роки тому

      @Salvador Marley glad I could help :)

  • @uggmonster8795
    @uggmonster8795 7 років тому +2

    You did not fully explain why we change the K in x+k and can be confusing. We set x+k=0 and solve for x. This would have been easier to explain so when you tell us variables being multiplied by a number make this more complicated when it is the same proceedure.

  • @gilbertmartinez9910
    @gilbertmartinez9910 8 років тому +1

    Thanks khan academy for helping me with this now I can study in peace lol

  • @niloofareshghi8780
    @niloofareshghi8780 7 років тому +1

    is there a video with a second degree divisor?

  • @ramble21
    @ramble21 Рік тому +2

    W khan academy

  • @beary605
    @beary605 12 років тому +1

    but with the intuition he gives, that means there should be a way to divide by polynomials.

  • @beary605
    @beary605 12 років тому +1

    Can you explain the method of synthetic division with polynomials, such as (4x^3-2x^2+4)/(2x^2+5x+1)?

    • @user-rr2hu7yj3g
      @user-rr2hu7yj3g 3 роки тому +2

      You can't. Only works in f(x)/x-a format.

  • @metroid_gauntlet
    @metroid_gauntlet 7 років тому

    What do you do if x has a coefficient with it? Like x-3, what if you had 2x-3 instead, what would you have to do?

    • @romacarlos3401
      @romacarlos3401 7 років тому

      he said in the video that it doesn't work if it has a coefficient.

    • @MarkCarrollGrumpyBear
      @MarkCarrollGrumpyBear 6 років тому

      not true. it will work if it has a coefficient; you just have to divide the denominator by whatever the coefficient is to make it a coefficient of 1

  • @xTESTimonyx
    @xTESTimonyx 9 років тому +26

    and this is why I hate math...

  • @kingle1775
    @kingle1775 9 років тому +1

    Can you add a complex one with some thing divided by 2x-3?

    • @kingle1775
      @kingle1775 9 років тому +1

      and it's not impossible

    • @Formula_Chase
      @Formula_Chase 8 років тому +1

      Synthetic division only works with x's that have the coefficient of 1. You'd have to do long division.

    • @MarkCarrollGrumpyBear
      @MarkCarrollGrumpyBear 6 років тому +1

      no, you wouldn't. you just need to reduce the coefficient of the x term to 1 by dividing the binomial by whatever the coefficient is.

  • @samanthachan3241
    @samanthachan3241 10 років тому

    so how will you be able to solve this:
    14x^4+3x^3+x^2-6x+2/x^2-9x+20

    • @MarkCarrollGrumpyBear
      @MarkCarrollGrumpyBear 6 років тому

      that requires you to factor using synthetic division, which I learned about just recently. you need to take the factors of the constant term (plus or minus) and figure out what factors into the rest of the equation without the constant term using synthetic division. because it's a degree 4th polynomial, after you figure out what can factor into the equation, you need to factor it again using the x cubed polynomial and doing the same process as you did with the starting thing. you need to reduce it to an x squared term in order to have your whole answer, and if that x squared trinomial can factor further, then you need to factor it into its binomials.

  • @ranxu9832
    @ranxu9832 7 років тому

    shouldn't it be minus during ring the synthetic division process rather than plus???

  • @prakashsolanki9116
    @prakashsolanki9116 6 років тому +3

    What do you do if x has a degree with it

    • @cassialli1547
      @cassialli1547 6 років тому

      Synthetic division won't work, so you have to do long division.

  • @ashleymendez4533
    @ashleymendez4533 6 років тому

    What happens if the equation not in order by exponents

  • @idsamuel
    @idsamuel 11 років тому

    /watch?v=jqXSbmKn3gs
    The video is in Indonesian, but maybe you can watch the diagrams.
    It's called "Horner Kino", an addition to Horner's method to divide polynomials with binomials (or more i can't be sure) found by an Indonesian mathematician Sukino. Hope it helps ^^

  • @rubycosmo6279
    @rubycosmo6279 6 років тому +2

    This looks like voodoo.

  • @idsamuel
    @idsamuel 11 років тому

    It's in informal Indonesian language though haha.
    By the way I've tried with more than binomials and it works! You just have to add the rows and do the same concept as in the video I gave.
    I'm relieved that Indonesia still has contributions to science and math in this case, so Khan Academy can you make a video about this? I'm sure it will help people and Sukino's work can be appreciated by more people in the world.

  • @SofieDiaz
    @SofieDiaz 9 років тому

    Wait how did 160 become + 160 and how did 17x^2 become + 17x^2??

  • @josierosie8445
    @josierosie8445 9 років тому

    Why did you compare it to voodoo?

  • @xavieraguinaldo3661
    @xavieraguinaldo3661 8 років тому

    Is that a missing term

  • @irismarchant6752
    @irismarchant6752 7 років тому

    why does he separate the 487????

    • @f3lla776
      @f3lla776 7 років тому

      Iris Marchant because it's the remainder

  • @jasonlong5097
    @jasonlong5097 6 років тому +1

    who is the dude? I kind of want to know him.

  • @jasmineo7724
    @jasmineo7724 6 років тому

    Why 487/x-3???

    • @shubhamjain1328
      @shubhamjain1328 6 років тому

      Jasmine J that's what the logarithm says you separate out the last term from the answer and it is the remainder.

  • @levanbichinashvili989
    @levanbichinashvili989 6 років тому

    After watching this I realised how useless my professor is.......

  • @user-tw5ek1gg8j
    @user-tw5ek1gg8j 4 роки тому

    I understand everything except what is Voodoo?
    Are you referring to Wudu in Islam?
    How is this Wudu?