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solve the systems of equation:

 

3x+y=20

2x+3y=18         (no graph)

cesix  Oct 25, 2017
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 #1
avatar+78744 
+2

3x+y=20    ⇒  y =  20 - 3x   (1)

2x+3y=18   (2)

 

Sub (1)  into (2)  for y

 

2x + 3 [ 20 - 3x]  =  18    simplify

 

2x + 60 - 9x  =  18

 

-7x + 60  = 18       subtract 60 drom both sides

 

-7x  =  -42            divide both sides by -7

 

x = 6

 

And using (1)    y =  20 - 3(6)  =  20 - 18  =  2

 

 

cool cool cool

CPhill  Oct 25, 2017
 #2
avatar+12 
+1

thank you so much!! :)

cesix  Oct 25, 2017

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