Ответ:

  1. \(5x+5y=5(x+y)\);
  2. \(4a-4b=4(a-b)\);
  3. \(3c+15d=3(c+5d)\);
  4. \(-6m-9n=-3(2m+3n)\);
  5. \(ax+ay=a(x+y)\);
  6. \(bc-bd=b(c-d)\);
  7. \(ab+a=a(b+1)\);
  8. \(cy-c=c(y-1)\);
  9. \(-ma-a=-a(m+1)\).