Question 23704: How can i figure these linear equations out they are so confusing. For example, trying to find three ordered pairs, why three??
ex: y = 7- 4x
PLEASE HELP ME ASAP THANKS : )
Answer by rapaljer(4671)   (Show Source):
You can put this solution on YOUR website! y = 7- 4x
To find three ordered pairs, what they mean is to find three points on the line. You can pick any value you want to use for x, plug it in, and find y. Then you write the numbers within parentheses with the x value ALWAYS first. I recommend you use easy values for x, like x = 0, x=1, or x=2. ANY values will do. As to why three, I'm not sure. Maybe because TWO points determines a line, and use a third point for a check. There is no particular reason to stop at THREE points--you could find 6 or 8 points!!!
You might want to see my lesson plans in algebra.com about graphing and the slope of a line. I have about three lesson plans so far related to graphing.
Now, back to your problem:
y = 7- 4x
Let x = 0, then y = 7-4*0 = 7
Let x = 1, then y = 7-4*1 = 3
Let x = 2, then y = 7-4*2 = -1
As I said, you don't HAVE to stop at THREE. This is fun!! Let's do some more!
Let x = -1, then y = 7-4*(-1) = 7+4 =11
Let x = -2, then y = 7-4*(-2) = 7+8 = 15
And so on . . .
If you graph all these points, it should look like this:
R^2 at SCC
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