\[\boxed{\text{152\ (152).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[\textbf{а)}\ \frac{a^{2} - 25}{a + 3} \cdot \frac{1}{a^{2} + 5a} - \frac{a + 5}{a^{2} - 3a} =\]
\[= \frac{- ac - bc}{a(a + b)} = \frac{- c \cdot (a + b)}{a(a + b)} =\]
\[= - \frac{c}{a}\]
\[= \frac{2(y + a)}{a(x - 3)}\ \]