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Question 708224: At home sick so I don't have anyone to explain these things to me. How do you find three ordered pairs for the linear equations like x-y=3 or x+7=8 without the constant trial and error I've been doing? I keep trying different numbers but when I get three ordered pairs it doesn't go in an exact line on the graph.
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website!  is a linear relationship between  and  that pairs
each value of with just one value of , and
each value of with just one value of .
To find one pair, you assign a value to one variable (the or the ) and
solve to find the corresponding value of the other variable.
Choosing zero usually works well.
For  the equation turns into  or  , so  and you have the pair (0,-3).
For  the equation turns into  , so  and you have the pair (3,0).
For a third pair, you can chose any number that works for you.
If all you need is a pair, the choice is easier.
In this case, you could chose  -->  -->  -->  and would have (5,2) for the third point.
If you want to use points to graph the line, it may get trickier,
but if your first choice does not work well for graphing, you can try again.
 would just give you a value for x, but no value for y.
There is no one-to-to one relationship between between and there.
The equation is the equation of a "vertical" line,
made of all the points that have
 -->  and  
Your choices for points are as infinite as with any line,
but they are also infinitely easy:
(1,-5), (1,0), (1,3), (1,5.5), or (1,anything).
You may have meant meant  . If so, just try the same strategies that I described for the other equation.
-->  -->  may not look good to you,
but giving values to may be more to your liking.
-->  gives you point (8,0)
 -->  -->  -->  gives you (15,1).
-->  -->  -->  gives you (22,1).
 -->  --> --> --> gives you (1,-1).
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