SOLUTION: 9x+2y=-9,18x-5y=-18

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Question 449011: 9x+2y=-9,18x-5y=-18
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

9x%2B2y=-9,
18x-5y=-18

Solved by pluggable solver: Solve the System of Equations by Graphing



Start with the given system of equations:


9x%2B2y=-9

18x-5y=-18





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


9x%2B2y=-9 Start with the given equation



2y=-9-9x Subtract 9+x from both sides



2y=-9x-9 Rearrange the equation



y=%28-9x-9%29%2F%282%29 Divide both sides by 2



y=%28-9%2F2%29x%2B%28-9%29%2F%282%29 Break up the fraction



y=%28-9%2F2%29x-9%2F2 Reduce



Now lets graph y=%28-9%2F2%29x-9%2F2 (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+%28-9%2F2%29x-9%2F2%29+ Graph of y=%28-9%2F2%29x-9%2F2




So let's solve for y on the second equation


18x-5y=-18 Start with the given equation



-5y=-18-18x Subtract 18+x from both sides



-5y=-18x-18 Rearrange the equation



y=%28-18x-18%29%2F%28-5%29 Divide both sides by -5



y=%28-18%2F-5%29x%2B%28-18%29%2F%28-5%29 Break up the fraction



y=%2818%2F5%29x%2B18%2F5 Reduce





Now lets add the graph of y=%2818%2F5%29x%2B18%2F5 to our first plot to get:


Graph of y=%28-9%2F2%29x-9%2F2(red) and y=%2818%2F5%29x%2B18%2F5(green)


From the graph, we can see that the two lines intersect at the point (-1,0) (note: you might have to adjust the window to see the intersection)