Ответ:

  1. \(2x+2y=2(x+y)\);
  2. \(3a+3b=3(a+b)\);
  3. \(5m-5n=5(m-n)\);
  4. \(10p-5q=5(2p-q)\);
  5. \(12c+8d=4(3c+2d)\);
  6. \(15k-9l=3(5k-3l)\).