Ответ:

  1. \(126 : 9 = 14\).
  2. \(21 : x = \frac{21}{x}\).
  3. \((a+21) : 45 = \frac{a+21}{45}\).
  4. \(26 : (2a+b) = \frac{26}{2a+b}\).
  5. \(152 : (x+2y) = \frac{152}{x+2y}\).
  6. \((a+b) : (a-b) = \frac{a+b}{a-b}\).