Ответ:

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Ответ:

1) 10x + 15 = 7x + 6

  3x + 9 = 0

  x = -3

2) 3(4x - 1) + 5x = 14

  12x - 3 + 5x - 14 = 0

  17x - 17 = 0

  x = 1

3) 4x + 8 = 6x + 4(5x + 2)

  4x + 8 = 6x + 20x + 8

  4x + 8 - 26x - 8 = 0

  -22x = 0

  x = 0

4) 7(2x - 5) - 5(4x + 3) = 4x

  14x - 35 - 20x - 15 - 4x = 0

  -10x - 45 = 0

  10x + 45 = 0

  x = 4,5

5) 8 - 7(2 - 5x) - 4(2x + 3) = 3x

  8 - 14 + 35x - 8x - 12 - 3x = 0

  -18 + 24x = 0

  24x - 18 = 0

  x = 0,75

6) 2,1(x - 0,3) + 0,7x = 2,8x + 0,7

  2,1x - 0,63 + 0,7x - 2,8x - 0,7 = 0

  -1,33 = 0

   x = ∅