x and y graphs?

[IWantSomeCookies]

basically i have 2 co-ordinates, and i need to like work out an equation that works out the rest of the graph?

it's a linear graph, so these 2 co-ordinates are all i need, but i need help being pointed into the right directions..

oh and the co-ordinates are if anyone cares are:

0,100
455,-374

(im not looking for an answer here, im looking for atleast an explantion, if not a tutorial how to work these damn things out! :D)

[ratchet103]

At 9/29/09 03:02 PM, IWantSomeCookies wrote: basically i have 2 co-ordinates, and i need to like work out an equation that works out the rest of the graph?

it's a linear graph, so these 2 co-ordinates are all i need, but i need help being pointed into the right directions..

oh and the co-ordinates are if anyone cares are:

0,100
455,-374

(im not looking for an answer here, im looking for atleast an explantion, if not a tutorial how to work these damn things out! :D)

lacking english and math knowledge make me post this post in this thread.

sorry that i can't help ya

[Tramps]

At 9/29/09 03:02 PM, IWantSomeCookies wrote: basically i have 2 co-ordinates, and i need to like work out an equation that works out the rest of the graph?

I assume you want the equation of the line.

it's a linear graph, so these 2 co-ordinates are all i need, but i need help being pointed into the right directions..

oh and the co-ordinates are if anyone cares are:

0,100
455,-374

If you want to work out the answer, these are important.

So, you have two co-ordinates (0, 100) and (455, -374). Both follow the same (x, y) format so I'm going to call (0, 100); (x1, y1) and (455, -374); (x2, y2).

To work out the gradient of the line, you have to do y2 - y1 / x2 - x1. So that's 455 - 0 = 455 and -374 - 100 = -474. So the gradient is 455 / -474. That can't be simplified. Which is a little odd so I don't blame me if I'm wrong.

The process for working out the equation of a line is: y - y1 = m(x - x1).

So substitute the values in: y - 100 = 455/-474 (x - 0)
Multiply it out: y - 100 = 455/-474x - 0
Balance the equation: y = 455/-474x + 100

Equation of the line is y = 455/-474x + 100

I believe that's the equation of the line if I didn't go wrong anywhere.

[142201]

Lucky you, I have the very equations for finding the distance and slope of a line based on the coordinates of the endpoints sitting here in my calculator.

But woudn't you know it, I archived them. To unarchive a program is a lot of work. Why should I bother?

I'm so mean.

[142201]

At 9/29/09 03:13 PM, Tramps wrote: The answer.

Awwww...

[GoryBlizzard]

You have these two given points:

(455, -374) and (0, 100)

Let x1 = 455, y1 = -374, x2 = 0 and y2 = 100.

The first thing you want to do is to find the slope, m.

m = (y2 - y1)/(x2 - x1) = (100 - (-374))/(0 - 455)
m = (100 + 374)/-455
m = -474/455

The next step is simply finding the line's equation by plugging all of this into the point-slope form of a linear equation:

y - y1 = m(x - x1)
y - (-374) = -(474/455)(x - 455)
y + 374 = -(474/455)x(x - 455)
y + 374 = -(474/455)x + 474
y = -(474/455)x + 100

The equation of the line you're looking for is therefore y = -(474/455)x + 100.

[K-Guare]

At 9/29/09 03:13 PM, Tramps wrote: To work out the gradient of the line, you have to do y2 - y1 / x2 - x1. So that's 455 - 0 = 455 and -374 - 100 = -474. So the gradient is 455 / -474. That can't be simplified. Which is a little odd so I don't blame me if I'm wrong.

Slope of a line is deltaY / deltaX, you have them reversed.
From what I see, everything else you did is right though.

Yay, Algebra I !

[Kwing]

Aren't there like 3 different ways to write a linear equation?

[TheLameSauce]

rise over run is the slope. use the slope to algebraically solve the intercept. what are you twelve or retarded?

[Claxor]

Short version:
(0,100) sais: 0k+m=100 <==> m=100
(455,-374) sais: 455k+100=-374 <==> k=-1.0417582.. (the digits 417582 repeat indefinitely).

[lawlmaster]

this guy would know alot about them.