Divide 3n^2-n/n^2-1/n^2/n+1

To simplify the given expression, we have:

(3n^2 - n) / ((n^2 - 1) / (n^2 / (n + 1)))

We can start by simplifying the denominator's denominator, which is n^2 / (n + 1). This can be rewritten as (n^2 * 1 / (n + 1)).

The expression now becomes:

(3n^2 - n) / ((n^2 - 1) / (n^2 * 1 / (n + 1)))

Next, we can simplify the numerator by factoring out the common term:

n(3n - 1)

The expression becomes:

(n(3n - 1)) / ((n^2 - 1) / (n^2 * 1 / (n + 1)))

Now, let's simplify the denominator by factoring it:

(n^2 - 1)

This is a difference of squares, which can be factored into:

(n + 1)(n - 1)

Since the denominator (n^2 - 1) is being divided by the entire expression (n^2 * 1 / (n + 1)), it becomes the numerator of the whole expression:

(n(3n - 1)) / ((n + 1)(n - 1))

So, the simplified form of the given expression is:

(n(3n - 1)) / ((n + 1)(n - 1)).