Ответ:

  1. \(14x+21y=7(2x+3y)\);
  2. \(15a+10b=5(3a+2b)\);
  3. \(8ab-6ac=2a(4b-3c)\);
  4. \(9xa+9xb=9x(a+b)\);
  5. \(6ab-3a=3a(2b-1)\);
  6. \(4x-12x^2=4x(1-3x)\);
  7. \(m^4-m^2=m^2(m^2-1)\);
  8. \(c^3+c^4=c^3(1+c)\);
  9. \(7x-14x^3=7x(1-2x^2)\).