http://i754.photobucket.com/albums/x...at111757AM.png

I need help with the 2nd part of the question, evaluating the limit at neg infinity.

I'm dividing the numerator by the highest power in the denominator (dividing everything by x^3 and x^6 under the radical) and I'm coming up with...

Lim x-> -oo f(x) = 3+6(1/x^3) / [3 + sqrt((36 + 4(1/x^6))]

1/x^3 approaches 0 as x approaches neg infinity and 1/x^6 approaches zero as x approaches infinity. leaving me with...

3 / [(3+sqrt(36)] =3 / (3+3) = 1/3.

The correct answer is -1. Where did I go wrong?