Ответ:

  1. \(\dfrac{(y-4)(y+4)}{3(y+4)}=\dfrac{y-4}{3}\).
  2. \(\dfrac{(c+2)^2}{7c(c+2)}=\dfrac{c+2}{7c}\).
  3. \(\dfrac{5(x-3y)}{(x-3y)(x+3y)}=\dfrac5{x+3y}\).
  4. \(\dfrac{6c(d-3)}{(d-3)^2}=\dfrac{6c}{d-3}\).
  5. \(\dfrac{(a+5)^2}{(a-5)(a+5)}=\dfrac{a+5}{a-5}\).
  6. \(\dfrac{(y-3)(y+3)}{(y-3)^2}=\dfrac{y+3}{y-3}\).

Ответ: а) \(\dfrac{y-4}{3}\); б) \(\dfrac{c+2}{7c}\); в) \(\dfrac5{x+3y}\); г) \(\dfrac{6c}{d-3}\); д) \(\dfrac{a+5}{a-5}\); е) \(\dfrac{y+3}{y-3}\).