Divide $\frac{16a^{3}-20a^{2}-45a-9}{\left(4a^{2}-9\right)\left(2a^{2}-2a-3\right)}$ by $\frac{a+1}{2a-3}$ by multiplying $\frac{16a^{3}-20a^{2}-45a-9}{\left(4a^{2}-9\right)\left(2a^{2}-2a-3\right)}$ by the reciprocal of $\frac{a+1}{2a-3}$.
Divide $\frac{16a^{3}-20a^{2}-45a-9}{\left(4a^{2}-9\right)\left(2a^{2}-2a-3\right)}$ by $\frac{a+1}{2a-3}$ by multiplying $\frac{16a^{3}-20a^{2}-45a-9}{\left(4a^{2}-9\right)\left(2a^{2}-2a-3\right)}$ by the reciprocal of $\frac{a+1}{2a-3}$.