SOLUTION: 3(x+y)- 4 (y-x)= 19 4(2x-y) + y = 18

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Question 318180: 3(x+y)- 4 (y-x)= 19
4(2x-y) + y = 18

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
3(x+y)- 4 (y-x)= 19
3x+3y -4y + 4x = 19
7x - y = 19
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4(2x-y) + y = 18
8x -4y + y = 18
8x-3y = 18
-----------------------
Solve this system:
7x - y = 19
8x - 3y= 18
----------------------
Solve for "y" in the 1st equation:
y = 7x-19
--------------
Substitute for "y" in the 2nd equation and solve for "x":
8x -3*(7x-19) = 18
---
8x - 21x + 57 = 18
-13x = -39
x = 3
-------------------
Since y = 7x-19, so y = 7*3-19 = 2
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Cheers,
Stan H.
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