Question 789115: plot the equation 3x+4y=7 on the graph paper taking four points. also plot the equation y=x on the same graph paper. at what point do the two lines meet?
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! To graph one line you only need to plot two points and connect them with a straight line. Since the problem asks for 4 points, we do the extra unnecessary work.
For  ,
--> --> , so chosing random values for  we would get lots of fractions.
However, substituting  gives us
{{y=(7-3)/4=4/4=1)}}} and we have the point (1,1).
Increasing or decreasing x by 4 gives us other integer values for y:
Substituting  gives us
 and we have the point (5,-2).
Substituting  gives us
 and we have the point (-3,4).
Substituting  gives us
 and we have the point (-7,7).
For  , nice points are easier to find:
We could substitute a few scattered values for x, to get
 --> for point (4,4),
 --> for point (8,8),
 --> for point (-4,-4), and
 --> for point (-8,-8)
 The lines seem to intersect at point (1,1), so  seems to be the solution.
We need to verify by substituting in the original equations:
For ,  checks
For ,  checks.
So  is the solution.
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