Verified answer

2х - (6х + 1) = 9

2х - 6х - 1 = 9

2х - 6х = 9 + 1

- 4х = 10

х = 10 : ( - 4)

х = - 2,5

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2*(- 2,5) - (6*(-2,5) + 1) = 9

-5 - (- 15 + 1) = 9

-5 - (-14) = 9

-5 + 14 = 9

9 = 9

Ответ: х = - 2,5