Пошаговое объяснение:

1)

[tex]7(x - 1) = 4x \\ 7x - 7 = 4x \\ 7x = 4x + 7 \\ 7x - 4x = 7 \\ 3x = 7 \\ x = 7 \div 3 \\ x = \frac{7}{3} [/tex]

Проверка:

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[tex]7( \frac{7}{3} - 1) = 4 \times \frac{7}{3} [/tex]

2)

[tex] - 5(3 - x) = 6(x + 1) \\ - 15 + 5x = 6( x + 1) \\ - 15 + 5x = 6x + 6 \\ - 15 + 5x - 6x = 6 \\ 5x - 6x = 6 + 15 \\ - x = 6 + 15 \\ - x = 21 \\ x = - 21[/tex]

Проверка:

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[tex] - 5(3 + 21) = 6( - 21 + 1)[/tex]