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Ответ:

[tex]x + 4y = - 1 \\ - \\ x + y = 5 \\ \\ x - x + 4y - y = - 1 - 5 \\ 3y = - 6 \\ y = - 2 \\ \\ x + y = 5 \\ x = 5 - y = 5 + 2 = 7[/tex]