Ответ:

  1. \(2x=5x+9\)
    \(2x-5x=9\)
    \(-3x=9\)
  2. \(6x-8.4=-8.4\)
    \(6x=-8.4+8.4\)
    \(6x=0\)
  3. \(-1.5x+4=-4.3x-9\)
    \(-1.5x+4.3x=-9-4\)
    \(2.8x=-13\)
  4. \(19x+14=16y+14\)
    \(19x-16y=14-14\)
    \(19x-16y=0\)
  5. \(-x+24y-9=x-17y+23\)
    \(-x-x+24y+17y=23+9\)
    \(-2x+41y=32\)
  6. \(54.3a-18.5b=-11.3b-78\)
    \(54.3a-18.5b+11.3b=-78\)
    \(54.3a-7.2b=-78\)