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Question 549153: I have to graph 2x+3y=9. Is that more than one coordinate, and what are the coordinates?
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! To graph points with two coordinates you need a set of perpendicular coordinate axes. Using grid paper makes it easier. I'll show you a drawing. A point with x=3 and y=1, is represented as (3, 1) and plotted like this:
  is a linear relation, and its graph is a straight line.
Because you only need two points to determine a line, it should be easy.
You could choose  , substitute in the equation and find 
 --->  ---> 
and dividing both sides of the equal sign by 3 
Now you have point (0,3), with , as one of the points in the line.
You could also chose  and substitute to find
 --->  --->  <-->
That would give you (9/2,0), with , as a second point in the line.
They are reasonable spaced, and I can make them appear somewhat centered on my graph, if I choose the scale on each axis wisely. Then, I can draw the line that passes through those points,like this:
 I almost always redo my graphs, changing something to make them look better.
I consider the first try just a rough draft, unless I just get lucky with it.
And, yes. I had picked the first (red) point I plotted so that it would fall on the line too.
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