Ответ:

  1. \(\frac{a^3-ab^2}{a^2-ab}=\frac{a(a-b)(a+b)}{a(a-b)}=a+b\), при \(a\ne0\), \(a\ne b\).
  2. \(\frac{6x^2+12x}{2x^2-8}=\frac{6x(x+2)}{2(x-2)(x+2)}=\frac{3x}{x-2}\), при \(x\ne2\), \(x\ne-2\).
  3. \(\frac{3m^2-6mn+3n^2}{6m-6n}=\frac{3(m-n)^2}{6(m-n)}=\frac{m-n}{2}\), при \(m\ne n\).
  4. \(\frac{c^3-c}{c^2-c}=\frac{c(c-1)(c+1)}{c(c-1)}=c+1\), при \(c\ne0\), \(c\ne1\).
  5. \(\frac{ay^2+a^2y}{a^3y-ay^3}=\frac{ay(a+y)}{ay(a-y)(a+y)}=\frac{1}{a-y}\), при \(a\ne0\), \(y\ne0\), \(a\ne y\), \(a\ne-y\).