Question

Упростите выражение$( frac{2n-4}{n-1} - frac{n}{n+1}) :( n^{2}-n-4)$

Answer 1

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