SOLUTION: for graphing.....2x-7y=8 and 3x-4y=-1

Algebra ->  Expressions-with-variables -> SOLUTION: for graphing.....2x-7y=8 and 3x-4y=-1      Log On


   

Question 120451: for graphing.....2x-7y=8 and 3x-4y=-1
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: Solve the System of Equations by Graphing



Start with the given system of equations:


2x-7y=8

3x-4y=-1





In order to graph these equations, we need to solve for y for each equation.




So let's solve for y on the first equation


2x-7y=8 Start with the given equation



-7y=8-2x Subtract 2+x from both sides



-7y=-2x%2B8 Rearrange the equation



y=%28-2x%2B8%29%2F%28-7%29 Divide both sides by -7



y=%28-2%2F-7%29x%2B%288%29%2F%28-7%29 Break up the fraction



y=%282%2F7%29x-8%2F7 Reduce



Now lets graph y=%282%2F7%29x-8%2F7 (note: if you need help with graphing, check out this solver)



+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+%282%2F7%29x-8%2F7%29+ Graph of y=%282%2F7%29x-8%2F7




So let's solve for y on the second equation


3x-4y=-1 Start with the given equation



-4y=-1-3x Subtract 3+x from both sides



-4y=-3x-1 Rearrange the equation



y=%28-3x-1%29%2F%28-4%29 Divide both sides by -4



y=%28-3%2F-4%29x%2B%28-1%29%2F%28-4%29 Break up the fraction



y=%283%2F4%29x%2B1%2F4 Reduce





Now lets add the graph of y=%283%2F4%29x%2B1%2F4 to our first plot to get:


Graph of y=%282%2F7%29x-8%2F7(red) and y=%283%2F4%29x%2B1%2F4(green)


From the graph, we can see that the two lines intersect at the point (-3,-2) (note: you might have to adjust the window to see the intersection)