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## graphing linear equations?  1-Newbie

## graphing linear equations?

??? how do you do that? here's an example:
8x-y=16 the only thing i think i know is that...i think you only get one point and it wil just make one straight line? we're having a test on it i think next friday....but i have work on it due tomorrow!
6 REPLIES 6  1-Newbie
(To:angels-disabled)
In the case of 8x-y=16, the ordered pair (3,8) satisfies the equation. Can you find another pair that also satisfies it? You then plot the two points and draw the line.
PKA  1-Newbie
(To:pkalford-disabl)
O.K.? well...we did something like...get rid of x and somehow find y? i don't know..but, what about a problem such as... 2x-5y=12?...i just made that up! so i'm not sure if it will work?  1-Newbie
(To:angels-disabled)
Look, ordered pairs are points in the plane. Lines are collections of points in the plane. These points, (p,q), satisfy the equations of lines, ax+by=c, that is a*p+b*q=c. All I have to do is find two points (u,v) & (t,s) such that a*u+b*x=c & a*t+b*s=c. Two points determine a line! The way we find these points is not fixed. So you may solve for one of the variables, either x or y. But, this is not necessary! To graph a line, all we need is two points.
PKA  1-Newbie
(To:pkalford-disabl)
??? how do you do that? here's an example:
8x-y=16 the only thing i think i know is that...i think you only get one point and it wil just make one straight line? we're having a test on it i think next friday....but i have work on it due tomorrow!

first you isolate the "y" to get it by itself ( almost )

8x-y=16
+y +y
8x=16+y

subtract 16

8x-16=y
then you just pick points:
lets say you want s to be 3
substitute:

8(3)-16=y
24-16=y
8=y  1-Newbie
(To:jackal_1500-dis)
sorry, jackal_1500
this is from Laura  1-Newbie
(To:jackal_1500-dis)
Angel,

When you mentioned you were confused about your teacher asking you to get rid of the x term, I think you were remembering about the y-intercept, which is where a line crosses the y-axis. At that point x = 0.

So in your equation, 8x - y = 16
Set x = 0.

8*0 - y = 16
0 - y = 16

- y = 16

y = -16

So one point on your line is (0,-16).
Now you have two points, with the one found earlier.

For any line, you can try a value for x in the equation, then find a matching value for y to find a point on the line.

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