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how to solve 7y-3x=-27 and 4x-y-11=0

 May 17, 2015

Best Answer 

 #1
avatar+128079 
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7y-3x=-27 and 4x-y-11=0

 

Using the second equation, we can write it as  y = 4x - 11    .....and substituting this in for "y" in  the frist equation, we have

 

7(4x - 11) - 3x = -27

 

28x - 77 - 3x  = -27

 

25x  - 77  = -27      add 77 to both sides

 

25x  = 50         divide both sides by 2

 

x = 2       and y = 4(2) - 11  = 8 - 11  = -3

 

So    (x, y)  =  (2, -3)

 

 

 May 17, 2015
 #1
avatar+128079 
+10
Best Answer

7y-3x=-27 and 4x-y-11=0

 

Using the second equation, we can write it as  y = 4x - 11    .....and substituting this in for "y" in  the frist equation, we have

 

7(4x - 11) - 3x = -27

 

28x - 77 - 3x  = -27

 

25x  - 77  = -27      add 77 to both sides

 

25x  = 50         divide both sides by 2

 

x = 2       and y = 4(2) - 11  = 8 - 11  = -3

 

So    (x, y)  =  (2, -3)

 

 

CPhill May 17, 2015

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