need some help with with graphing

• Sep 21st 2006, 10:17 PM
robpez
need some help with with graphing
I need some help with with graphing liner equations. i am supposed to get 3 order pair solutions then graph it.the thing i am having the most trouble with is geting the 3 order pair aolutions. here are two sample problems. thanks for the help

x-2y=6

3y-10=5x
• Sep 21st 2006, 10:56 PM
ticbol
Quote:

Originally Posted by robpez
I need some help with with graphing liner equations. i am supposed to get 3 order pair solutions then graph it.the thing i am having the most trouble with is geting the 3 order pair aolutions. here are two sample problems. thanks for the help

x-2y=6

3y-10=5x

An ordered pair here is a point on the graph. Since you have the usual x and y, then an ordered pair is in the form (x,y).
For every value of x, there is a corresponding value of y, and these two values are the ordered pair on that specific point on the graph.

Getting ordered pair is easy as pie. You assign a value to, say, x, then you solve for the y.
Example,
x -2y = 6
Say, x=0, so,
0 -2y = 6
y = 6/(-2) = -3
Hence, the ordered pair here is (0,-3).

You need 3 ordered pairs for this equation. You need two more.

say, x=2, then,
2 -2y = 6
-2y = 6 -2 = 4
y = 4/(-2) = -2
Hence, (2,-2) is another ordered pair.

Last one, say x=4,
4 -2y = 6
-2y = 6 -4 = 2
y = 2/(-2) = -1
Hence, (4,-1), your 3rd ordered pair.

Plot those on the same x,y axes, draw a line through them, and you have your graph of the line x -2y = 6.

Now try the second line.
• Sep 23rd 2006, 01:18 AM
robpez
[QUOTE=ticbol;21358]An ordered pair here is a point on the graph. Since you have the usual x and y, then an ordered pair is in the form (x,y).
For every value of x, there is a corresponding value of y, and these two values are the ordered pair on that specific point on the graph.

Getting ordered pair is easy as pie. You assign a value to, say, x, then you solve for the y.
Example,
x -2y = 6
Say, x=0, so,
0 -2y = 6
y = 6/(-2) = -3
Hence, the ordered pair here is (0,-3).

You need 3 ordered pairs for this equation. You need two more.

say, x=2, then,
2 -2y = 6
-2y = 6 -2 = 4
y = 4/(-2) = -2
Hence, (2,-2) is another ordered pair.

Last one, say x=4,
4 -2y = 6
-2y = 6 -4 = 2
y = 2/(-2) = -1
Hence, (4,-1), your 3rd ordered pair.

I am still a little confused. in the last problem where did you get the -4
• Sep 23rd 2006, 02:13 AM
CaptainBlack
[quote=robpez;21468]
Quote:

Originally Posted by ticbol
An ordered pair here is a point on the graph. Since you have the usual x and y, then an ordered pair is in the form (x,y).
For every value of x, there is a corresponding value of y, and these two values are the ordered pair on that specific point on the graph.

Getting ordered pair is easy as pie. You assign a value to, say, x, then you solve for the y.
Example,
x -2y = 6
Say, x=0, so,
0 -2y = 6
y = 6/(-2) = -3
Hence, the ordered pair here is (0,-3).

You need 3 ordered pairs for this equation. You need two more.

say, x=2, then,
2 -2y = 6
-2y = 6 -2 = 4
y = 4/(-2) = -2
Hence, (2,-2) is another ordered pair.

Last one, say x=4,
4 -2y = 6
-2y = 6 -4 = 2
y = 2/(-2) = -1
Hence, (4,-1), your 3rd ordered pair.

I am still a little confused. in the last problem where did you get the -4

The minus four comes from moving the 4 on the left hand side of:

4 - 2y = 6

over to the right hand side.

You can think of it as subtracting 4 from both sides of the equation:

(4 - 2y) -4 = (6) -4,

so:

4 - 2y -4=-2y=6-4=2,

which leaves us with:

-2y=2

hence:

y=2/(-2)=-1.

RonL