Упростите выражение: ((a-2)/(a+2)-(a+2)/(a-2))∶(12a^2)/(4-a^2).

\[\left( \frac{a - 2^{\backslash a - 2}}{a + 2} - \frac{a + 2^{\backslash a + 2}}{a - 2} \right)\ :\frac{12a^{2}}{4 - a^{2}} =\]

\[= \frac{- 4 \cdot 2a \cdot ( - 1)}{12a^{2}} =\]

\[= \frac{8a}{12a^{2}} = \frac{2}{3a}\]