10x - 7y = -1....multiply by -1 to make that -7y positive
-2x - 7y = -25
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-10x + 7y = 1 (result of multiplying by -1)
-2x - 7y = -25
-----------------add
-12x = - 24
x = 2
-2x - 7y = -25
-2(2) - 7y = -25
-4 - 7y = -25
-7y = - 25 + 4
-7y = - 21
y = 3
solution is : (2,3)