Упростите выражение (n+1/n^2+4n+4 - n-1/n^2-4) : 2n/(n+2)^2

Решите задачу:

$( \frac{n+1}{ n^{2} +4n+4}- \frac{n-1}{ n^{2} -4} ): \frac{2n}{(n+2) ^{2} }=( \frac{n+1}{(n+2) ^{2} } - \frac{n-1}{(n-2)(n+2)} ): \frac{2n}{(n+2) ^{2} }=$ $\frac{(n+1)(n-2)-(n-1)(n+2)}{(n+2) ^{2}(n-2) }: \frac{2n}{(n+2) ^{2} } = \frac{ n^{2}-2n+n-2- n^{2}-2n+n+2}{(n+2) ^{2}(n-2) }* \frac{(n+2) ^{2} }{2n} =$ $\frac{-2n}{n-2}* \frac{1}{2n}= \frac{1}{2-n}$