Упростите выражение ((a+4)/(a-4)-(a-4)/(a+4))∶48a/(16-a^2).

\[\left( \frac{a + 4^{\backslash a + 4}}{a - 4} - \frac{a - 4^{\backslash a - 4}}{a + 4} \right)\ :\frac{48a}{16 - a^{2}} =\]

\[= \frac{(a + 4)^{2} - (a - 4)^{2}}{(a - 4)(a + 4)}\ :\frac{- 48a}{a^{2} - 16} =\]

\[= \frac{(a + 4 - a + 4)(a + 4 + a - 4)}{(a - 4)(a + 4)}\ :\frac{- 48a}{(a - 4)(a + 4)} =\]

\[= \frac{8 \cdot 2a \cdot (a - 4)(a + 4)}{(a - 4)(a + 4) \cdot ( - 48) \cdot a} = - \frac{1}{3}\]