Question 245800
You have two unknowns and two equations:
9x-9y=9
7y-3x=-5
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Reordering the second equation:
 9x-9y=9
-3x+7y=-5
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The idea is to combine (add) both equations together to get rid of one of the unknowns.  
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We start by multiplying the second equation by 3:
 9x-9y=9
3(-3x+7y)=3(-5)
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 9x-9y=9
-9x+21y=-15
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Now, we add the two equations together:
 9x-9y=9
-9x+21y=-15
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    12y=-6
      y = -6/12
      y = -1/2
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Substitute the above into our original first equation:
9x-9y=9
9x-9(-1/2)=9
9x-(-9/2)=9
9x+9/2=9
x+1/2=1
x = 1-1/2
x = 1/2
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Solution:
(x,y) = (1/2, -1/2)