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

\[\left( \frac{a - 2^{\backslash a - 2}}{a + 2} - \frac{a + 2^{\backslash a + 2}}{a - 2} \right)\ :\frac{2a}{4 - a²} =\]

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

\[= \frac{- 8a\left( 4 - a^{2} \right)}{- \left( 4 - a^{2} \right) \cdot 2a} = 4\]