Ответ:

  1. \(12\cdot3x=36x\).
  2. \(10x\cdot6=60x\).
  3. \(5a\cdot7b=35ab\).
  4. \(8m\cdot12n=96mn\).
  5. \(2a\cdot3b\cdot4c=24abc\).
  6. \(5x\cdot2y\cdot10z=100xyz\).

Ответ: 1) 36x; 2) 60x; 3) 35ab; 4) 96mn; 5) 24abc; 6) 100xyz.