1) x+9= -9x

2)3x-8= -x

3) -7=5(x+5)



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Решение и ответ:

1) x + 9 = -9x

  x + 9x = -9

  10x = -9

   x = -9 ÷ 10

  x = -0.9

2) 3x - 8 = -x

    3x + x = 8

    4x = 8

    x = 8 ÷ 4

    x = 2

3) -7 = 5(x + 5)

   -7 = 5x + 25

    5x = -7 - 25

    5x = -32

    x = -32 ÷ 5

    x = -6.4