Answer:
(n -1)(n +1)(n +7) = x³ +7x² -x -7
Explanation:
The least common denominator is the product of the unique denominator factors.
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The factors of the denominator of n/(n^2-1) are (n -1)(n +1).
The factors of the denominator of 3n/(n^2+8n+7) are (n +7)(n +1).
The product of the unique factors is ...
(n -1)(n +1)(n +7) = x³ +7x² -x -7 . . . . least common denominator