Ответ:

  1. \(8x + 7x = 1515\)
    \(15x = 1515\)
    \(x = 101\).
  2. \(8 \cdot (2x - 6) = 128\)
    \(2x - 6 = 128 : 8 = 16\)
    \(2x = 22\)
    \(x = 11\).

Ответ: а) \(x = 101\); б) \(x = 11\).