Worked example: evaluating functions from graph | Algebra (video) | Khan Academy (2024)

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  • calebjohndavidson

    a year agoPosted a year ago. Direct link to calebjohndavidson's post “t3he thing about this is ...”

    t3he thing about this is khan is a very smart and buetifull man, he never failrs to disapoing anytbody. he healps so mach with peopoles masths

    (13 votes)

    • ninaruoliu

      5 months agoPosted 5 months ago. Direct link to ninaruoliu's post “what's up with yo spellin...”

      what's up with yo spelling?

      (6 votes)

  • Sujesh Devdassahastrabuddeheshanticurry Ramkrishnabhagawan

    7 years agoPosted 7 years ago. Direct link to Sujesh Devdassahastrabuddeheshanticurry Ramkrishnabhagawan's post “Why is it always f(x) and...”

    Why is it always f(x) and not any other letters?

    (12 votes)

    • David Severin

      7 years agoPosted 7 years ago. Direct link to David Severin's post “Wait until you get to Alg...”

      Worked example: evaluating functions from graph | Algebra (video) | Khan Academy (7)

      Wait until you get to Algebra 2 when you have to start combining multiple functions, you will start seeing g(x), h(x) etc. In Algebra I, you are just getting used to functional notation, but the power of functional notation over y= form will come later.

      (15 votes)

  • why is the video so short

    (15 votes)

    • Mostafa

      a year agoPosted a year ago. Direct link to Mostafa's post “why aren't all the videos...”

      Worked example: evaluating functions from graph | Algebra (video) | Khan Academy (11)

      why aren't all the videos so short

      (13 votes)

  • Sterling Holmes

    3 years agoPosted 3 years ago. Direct link to Sterling Holmes's post “I don't understand someth...”

    I don't understand something. When asked to find f(x), what am I being asked to find? Where do I look to find it?

    (6 votes)

    • Chic- Fila

      3 years agoPosted 3 years ago. Direct link to Chic- Fila's post “When it says 'f(x)' it is...”

      Worked example: evaluating functions from graph | Algebra (video) | Khan Academy (15)

      When it says 'f(x)' it is generally talking about the y. So when you write an equation like f(x)=2x+3. it in other words is saying y=2x+3.

      I hope that made some sort of sense... If you want me to explain it in greater detail.. just let me know! <3

      (17 votes)

  • lotuswells999

    9 years agoPosted 9 years ago. Direct link to lotuswells999's post “How to graph a Parabola”

    How to graph a Parabola

    (5 votes)

    • Aaron Ghosh

      a year agoPosted a year ago. Direct link to Aaron Ghosh's post “A Parabola could be graph...”

      A Parabola could be graphed when given the following skeleton equation: ax^2+bx+c. However, it is not easy to explain how to graph parabolas over comments, so it would be much wiser to follow MyAnchorHolds' suggestion and view the videos on Khan Academy.

      (4 votes)

  • jsrodriguez

    4 years agoPosted 4 years ago. Direct link to jsrodriguez's post “What if the function is f...”

    What if the function is f(-3) but there’s two points going vertically thru -3

    (7 votes)

    • loumast17

      4 years agoPosted 4 years ago. Direct link to loumast17's post “Then it is not a function...”

      Then it is not a function. A function can only have one y value for every x value. Important to remember there can be multiple x values for a single y value. Kind of confusing but important to remember. if you know it, the vertical line test will tell you if something is a function.

      (7 votes)

  • Abu Backer Sayeed

    8 years agoPosted 8 years ago. Direct link to Abu Backer Sayeed's post “can anyone please tell me...”

    can anyone please tell me what would be the answer of
    f : x > x^2 -5x

    a) find the value of f(-2)
    b) find the value of ff(2)
    c) find the range of f if domain is {-1, 0, 1}

    it would be really grateful of you

    (7 votes)

    • David Severin

      8 years agoPosted 8 years ago. Direct link to David Severin's post “f(x)> x^2 - 5x so by subs...”

      f(x)> x^2 - 5x so by substitution,
      a) f(-2) > (-2)^2 - 5(-2) 4 - (- 10) = 14
      f(-2)> 14
      b) f(2) > (2)^2- 5(2) 4-10 = -6
      f(2) > -6
      c) f(-1) > (-1)^2 -5(-1) f(-1)> 6
      f(0) > 0^2 - 5(0 f(0) > 0
      f(1) = (1)^2 -5(1) f(1) > -4
      I have not seen this type of problem with limited domain with inequality, but
      since the range is the f(x),
      my best guess on how to write it would be {f(x)>6, f(x)>0, f(x)>-4}

      (6 votes)

  • rebpap2911

    6 years agoPosted 6 years ago. Direct link to rebpap2911's post “I do not get this at all ...”

    I do not get this at all I have a test in a few days, this is SO complicated. I need some help. PLEASE HELP ME
    And please answer fast

    (6 votes)

    • shaposhnikovd

      3 years agoPosted 3 years ago. Direct link to shaposhnikovd's post “I know this isn't really ...”

      I know this isn't really a fast answer, but,
      basically he is just saying that when the x coordinate is at -1, the y coordinate is 6 on the line.
      He just wants you to find out the y coordinate by using the line, when x (F) is given to you.
      Reply if you actually read this. you probably already got it, but ill write this anyway.

      (3 votes)

  • acealena

    4 years agoPosted 4 years ago. Direct link to acealena's post “Can I write the function ...”

    Can I write the function as f=x+1?

    (4 votes)

    • Neil

      4 years agoPosted 4 years ago. Direct link to Neil's post “My answer: kinda. You can...”

      My answer: kinda. You can write it like that, and it is technically correct, but it is common practice to either write it in: y=mx+b or f(x)=mx+b.
      Hope that helps!

      (5 votes)

  • Dallin Smith

    9 months agoPosted 9 months ago. Direct link to Dallin Smith's post “Sal Khan is smart, so why...”

    Sal Khan is smart, so why is the line all spaghetti like.

    (5 votes)

    • Bani Hundal

      9 months agoPosted 9 months ago. Direct link to Bani Hundal's post “This is hand drawn, so th...”

      This is hand drawn, so this is not that perfect though he's smart.

      (3 votes)

Worked example: evaluating functions from graph | Algebra (video) | Khan Academy (2024)

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