The rational functionfactorsas:

. . . . .

"Cancelling" gives us:

. . . . .

Evaluating at x = 3 results in:

. . . . .

So this looks good!

I will guess that all of "1 + x" is in the denominator, so the expression is as follows:

. . . . .

When dealing with problematic expressions containing radicals, it can often be useful to multiply by the conjugate, so let's try that here:

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. . . . .

. . . . .

"Cancelling" the common factor and then evaluating at x = -1 leads to the result you got. Excellent!