۱. $\frac{2a^{2}-16}{a^{2}-4} - (\frac{a-2}{a-2} \cdot a+4) = \frac{2a^{2}-16}{(a+2)(a-2)} - \frac{a^{2}+2a-8}{(a+2)(a-2)} = \frac{a^{2}-2a-8}{(a+2)(a-2)}$