Ответ:

[tex]8.6 - x = 3.8 \\ - x = 3.8 - 8.6 \\ - x = - 4.8 \\ x = 4.8[/tex]

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[tex]y + 5.4 = 7.1 \\ y = 7.1 - 5.4 \\ y = 1.7[/tex]