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Graphing a line given point and slope

Practice graphing a line given its slope and a point the line passes through.

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  • blobby green style avatar for user carter starling
    how do you do fractions
    (16 votes)
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    • female robot grace style avatar for user loumast17
      As a slope? you just need to remember rise over run. so if you had a fraction a/b where a and b are two numbers the slope is up by a and right by b, rise over run.

      if the slope is negative then your rise is negative, so you go down. or you could look at it as your run being negative so you go left. either way, the other is normal. so negative slope means either the rise goes down and run goes right OR rise goes up and run goes left.

      Let me know if that didn't help.
      (1 vote)
  • aqualine ultimate style avatar for user CHARL3S
    upvote if u here in 2022
    (15 votes)
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  • blobby green style avatar for user Tiffany Speakman
    Im still confused after watching this video
    (5 votes)
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  • aqualine ultimate style avatar for user Sheza Sajid
    why do we use (Y/X)coordinates instead of using (X/Y)?
    (0 votes)
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    • starky seed style avatar for user Dishita
      First of all, why do we consider something in the Y-axis and something else in the x-axis,
      by convention, the value of y (or f(x)) is dependent on the value of x right?
      so, the x-axis is generally considered as the independent value while the y-axis is the dependent value. (especially prevalent in physics, think of time(at least for classical mechanics), always in the x-axis cuz it doesn't depend on anything else,
      now that we got that covered,
      what does slope really mean?
      === what is the change in y values with change in the x values,
      if the slope is 3 we can say: the y value changes by 3 for every change in 1 unit in x value,
      it shows us the dependence of the dependent(y) and independent(x) values.
      we don't say a change in x/change in y as that doesn't really help us as we go further,
      why?
      alright, what does this really say?
      === what is the change in x to change in y? Does this really make sense?
      well, not really as it doesn't provide valuable information as *y is depending on x, not the other way around!*

      Thi concept proves very powerful as you learn calculus (literally, completely based on this simple, beautiful concept),
      quick spoiler, using differential calculus, you'd be able to find the slope for even a curved graph! This can help you find sooooo many stuff like the instantaneous velocity, etc, etc,!, using Integral calculus (closely inked to differential calculus), you can find the area under a graph and understand why and what that area provides!
      If you remember and understand this simple concept, it would be much easier (and more fun!) to understand the beautiful world of calculus, this is a basic, understand it well.

      If anything I've written is wrong or misleading, do let me know :)
      Hope this helps!
      Onwards!

      PS: I felt compelled to answer this question not only cuz it's an important basic but also due to the misleading 'answers' in the comment session (quite uncommon here in the KA community actually) of your question that indicate it is how it is,
      there is always a reason why (especially in math),
      keep questioning!
      (10 votes)
  • duskpin seedling style avatar for user zenziaud000
    The graph will not let me plot the coordinate, because the coordinate is on the very edge line.
    (4 votes)
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  • blobby green style avatar for user Dana Owens
    what is slope
    (2 votes)
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    • leaf green style avatar for user Aerin
      Slope is the change in y over change in x.
      To make things easier, it basically is
      ex) Slope of point (3 , 5) and point (-2 , -6)
      Lets say 5 and -6 is y in both points, and 3 and -2 is x,
      you just have to do 5-(-6) over 3-(-2) which is 11/5.
      or you can do -6-5 over -2-3 which is -11/-5, or 11/5.
      (4 votes)
  • aqualine ultimate style avatar for user Ella Wagenhofer
    How do you find the slope?
    (2 votes)
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  • marcimus pink style avatar for user Raindrop9
    Can I also solve it by setting up a slope equation and finding the y-intercept from there? For example, using the question from the video:

    y = -3
    x = 4

    -3 = -2(4) + b
    -3 = -8 + b
    -3 + 8 = -8 + 8 + b
    5 = b

    So our slope equation in completed form is y = -2x + 5. Hence, we can graph it by plotting (4,-3) and connecting it to (0,5), our y-intercept. I find this method quite convenient for me.
    (2 votes)
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  • aqualine ultimate style avatar for user Joshua Oh
    A line has a slope of 2 and includes the points (4,g) and (-9,-9). What is the value of g?
    ^^ help me out plz
    (2 votes)
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  • marcimus red style avatar for user Max Lemke
    how to do a fraction in a graph
    (2 votes)
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    • piceratops ultimate style avatar for user BlackmoonTheDragon
      Every fraction can be converted into a decimal. For example, 1/2 can be converted into 0.5, since 0.5 is the same as 1/2. Every other fraction can be converted in the same way. If you convert it into decimals, then you can put it into a graph in the correct way. Hope this helps!

      #YouKhanLearnAnything
      (1 vote)

Video transcript

- [Instructor] We are told graph a line with the slope of negative two, that contains the point four comma negative three. And we have our little Khan Academy graphing widget right over here, where we just have to find two points on that line, and then that will graph the line for us. So pause this video and even if you don't have access to the widget right now, although it's all available on Khan Academy, at least think about how you would approach this. And if you have paper and pencil handy, I encourage you to try to graph this line on your own, before I work through it with this little widget. All right, now let's do it together. So we do know that it contains point four comma negative three. So that's I guess you could say the easy part, we just have to find the point x is four y is negative three. So it's from the origin four to the right, three down. But then we have to figure out where could another point be? Because if we can figure out another point, then we would have graphed the line. And the clue here is that they say a slope of negative two. So one way to think about it is, we can start at the point that we know is on the line, and a slope of negative two tells us that as x increases by one, y goes down by two. The change in why would be negative two. And so this could be another point on that line. So I could graph it like this is x goes up by one, as x goes from four to five, y will go, or y will change by negative two. So why we'll go from negative three to negative five. So this will be done, we have just graphed that line. Now another way that you could do it, because sometimes you might not have space on the paper, or on the widget to be able to go to the right for x to increase, is to go the other way. If you have a slope of negative two, another way to think about it is, if x goes down by one, if x goes down by one, then y goes up by two. 'Cause remember, slope is change of y over change in x. So you could either say you have a positive change in y of two when x has a negative one change, or you could think of it when x is a positive one change, y has a negative two change. But either way notice, you got the same line. Notice this line is the same thing, as if we did the first way is we had x going up by one and y going down by two, it's the exact same line.