SOLUTION: 6x-7y=21 and 3x+7y=6 answer:(3, -3/7) need to know how my book got the -3/7 full break down please

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Question 186448: 6x-7y=21 and 3x+7y=6

answer:(3, -3/7)
need to know how my book got the -3/7 full break down please

Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
6x-7y=21
3x+7y=6
----------
Add to get:
9x = 27
x = 3
---------------
Substitute into 6x-7y=21 to solve for "y":
6(3) - 7y = 21
18 -7y = 21
7y = -3
y = -3/7
=============
Cheers,
Stan H.

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