решить систему уравнений 3x-2у=7
3X плюс 4у=25

{3x - 2у = 7    *(-1)

{3х + 4у = 25

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{-3x + 2у = -7    

{3х + 4у = 25

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{-3x + 2у = -7    

{6у = 18

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{-3x = -7 - 2у

{у = 3

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{3x = 7 + 2у

{у = 3

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{3x = 7 + 2*3

{у = 3

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{3x = 13

{у = 3

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{x = 13/3

{у = 3