5x - y = -7
3x - y = -2.....multiply by -1
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5x - y = -7
-3x + y = 2 (result of multiplying by -1)
------------add
2x = - 5
x = -5/2 or - 2.5
5x - y = -7
5(-2.5) - y = -7
-12.5 - y = -7
-12.5 + 7 = y
- 5.5 = y
solution is (-2.5 , -5.5)
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4x + 3y = 12.....multiply by 5
7x + 5y = 26....multiply by -3
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20x + 15y = 60 (result of multiplying by 5)
-21x - 15y = - 78 (result of multiplying by -3)
---------------------add
-x = - 18
x = 18
4x + 3y = 12
4(18) + 3y = 12
72 + 3y = 12
3y = 12 - 72
3y = - 60
y = -60/3
y = -20
solution is (18,-20)
