Ответ:
а)
\[\frac{x^2-a^2}{ax^3}\cdot\frac{ax^2}{x+a}=\frac{(x-a)(x+a)}{ax^3}\cdot\frac{ax^2}{x+a}=\frac{x-a}{x}.\]
б)
\[\frac{a^2-2ab}{6b^2}:\frac{a-2b}{3b}=\frac{a(a-2b)}{6b^2}\cdot\frac{3b}{a-2b}=\frac{a}{2b}.\]
в)
\[(y^2-4)\cdot\frac{3}{(y+2)^2}=\frac{(y-2)(y+2)\cdot3}{(y+2)^2}=\frac{3(y-2)}{y+2}.\]
г)
\[\frac{c^2-9c+9}{7c}:(3c-9)=\frac{c^2-9c+9}{7c(3c-9)}.\]
Ответ: а) \(\frac{x-a}{x}\); б) \(\frac{a}{2b}\); в) \(\frac{3(y-2)}{y+2}\); г) \(\frac{c^2-9c+9}{7c(3c-9)}\).
