Question

Mulitply ((n-5)/(n^2 - 2n -3)) / ((n-3)/(n^2 -4n - 5)).

Answer 1

((n-5)/(n^2 - 2n -3)) / ((n-3)/(n^2 -4n - 5))

multiply both sides by (n^2 - 2n -3)(n^2 - 4n - 5) , sometimes called cross-multiplying

n^3 - 4n^2 - 5n - 2n^2+ 8n + 10 = n^3 - 2n^2 - 3n - 3n^2 + 6n + 9
-n^2 = -1
n^2 = 1
n = ± 1