Math question: Algebra graphing

[Nocturnal]

So y = mx + b.

So if you have an equation or problem saying to graph y = 2x + 7, how do you get the answer to graph the thing onto a graph?

 

[InverseOfNeo]

2 is the slope of the line and y-intercept is at (0,7)

 

[Nocturnal]

Can you tell me why it's at (0, 7)? Will it always be at (0, b)?

 

[Sukhoi]

Originally posted by: Nocturnal
Can you tell me why it's at (0, 7)? Will it always be at (0, b)?

In that form, yes.

Think about it...if x=0 then the whole mx term is 0. That leaves y=b at x=0.

 

[Nocturnal]

And the slope, can you explain that to me? The slope is what on the x and y axes?

 

[mAdD INDIAN]

Originally posted by: Nocturnal
And the slope, can you explain that to me? The slope is what on the x and y axes?

slope = y1 - y/ ( x1-x)

Its pretty much the rate of change of the line.

 

[Sukhoi]

Slope is rise over run.

A slope of 2 is a rise of two over a run of 1 (since 2 is really 2/1).

 

[Kadarin]

The y intercept is where the line intersects the Y axis, so you assume x to be zero.

 

[Ender]

Um if you're learning this in class, I would think that the teacher would teach you the equation of a line since it's fundamental step in learning how to graph equations; however, I guess your teacher (if you have one) is a preatty lousy one.

 

[gopunk]

Originally posted by: Sukhoi
Slope is rise over run.

A slope of 2 is a rise of two over a run of 1 (since 2 is really 2/1).

yea... basically it means that if you look at the line, for every 2 units it moves upwards, it moves 1 unit in the positive x-direction, in this example.

 

[Hammyton]

Originally posted by: InverseOfNeo
2 is the slope of the line and y-intercept is at (0,7)

 

[Yossarian]

Or you could read the first page of that chapter in your math book, I'm sure it's all explained there 😉

 

[LivinLaVivaPollo]

 

[PCMarine]

Ahhhhhh....Junior High Algebra I

🙂

 

[phatj]

Say if you have a slope of 1...
think of it as going up one, over one.
If you have a slope of x..
go up x, over x.

You can make an X Y chart to help with the graph -
say your equation is y = 2x + 7
your chart would be
X | Y
-2 | 3
-1 | 5
0 | 7
1 | 9
2 | 11

so you know that the following points are on your graph: (-2,3) (-1,5) (0,7) (1,9) (2,11). Then you can just plot your points and graph.

 

[RossGr]

Originally posted by: phatj
Say if you have a slope of 1...
think of it as going up one, over one.
If you have a slope of x..
go up x, over x.

The last is not correct a slope of x mean up x over 1.

Up x over x is a slope of 1.

 

[Nocturnal]

Originally posted by: PipBoy
Or you could read the first page of that chapter in your math book, I'm sure it's all explained there 😉

Or if you would go play in traffic that would be nice, prick.

Just because I have questions doesn't mean you can act like a dick about it.

That's what I paid the $30.00 yearly subscription for. To ask questions like this when I feel like it, ok prick?

 

[Dudd]

Originally posted by: RossGr

Originally posted by: phatj
Say if you have a slope of 1...
think of it as going up one, over one.
If you have a slope of x..
go up x, over x.

The last is not correct a slope of x mean up x over 1.

Up x over x is a slope of 1.

A slope of x isn't a line, it is a parabola, so it shouldn't even enter this discussion.

 

[Yossarian]

Originally posted by: Nocturnal

Originally posted by: PipBoy
Or you could read the first page of that chapter in your math book, I'm sure it's all explained there 😉

Or if you would go play in traffic that would be nice, prick.

Just because I have questions doesn't mean you can act like a dick about it.

That's what I paid the $30.00 yearly subscription for. To ask questions like this when I feel like it, ok prick?

I am happy to have upset you! That's what I paid my $30 for. Ok? I especially like to mock lazy people like yourself that could have answered your own question with 5 minutes of reading.

 

[johnjohn320]

Hey Nocturnal, I would recommend talking to your teacher and asking to stay after school some time and get some help. Don't take this the wrong way (I struggled at first with basic algebra as well) but you're asking like, really basic questions almost every day it seems. Your teacher, sitting their with a pen and paper and actually showing you things will be able to help you.

Trust me, once you make that effort, it's like finding the key you didn't know existed. Junior high teachers will always be willing to stay after and help, and they'll remember that you made that effort. High school teachers are sometimes a different story.

 

[RossGr]

Originally posted by: Dudd

Originally posted by: RossGr

Originally posted by: phatj
Say if you have a slope of 1...
think of it as going up one, over one.
If you have a slope of x..
go up x, over x.

The last is not correct a slope of x mean up x over 1.

Up x over x is a slope of 1.

A slope of x isn't a line, it is a parabola, so it shouldn't even enter this discussion.

Actually a parabola y=x^2 has slope slope y'= 2x

I assumed that he was just generalizing the concept, and not speaking directly in terms of the coordinate system. so to rephrase it . let x be some unspecified number, a line with slope x means that it goes over 1 unit and up x units. A line that goes over x units and up x units has slope 1. This x is not tied to any specific coordinate system.