\[\boxed{\text{231\ (231).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[= \frac{5y + 15 + y - 3 - 4y + 18}{y^{2} - 9} =\]
\[= \frac{2y + 30}{y^{2} - 9}\]
\[= \frac{- 8}{2a - 3} = \frac{8}{3 - 2a}\]