17: You should get
Since it was argued that in the denominator the exponential prevails, and therefore the denominator tends to infinity, you have an indeterminate ratio here and thus you could use the l'Hospital rule. However, to be really precise and present the complete solution, you might be asked to show that the denominator indeed tends to infinity, which is extra work.
Can you avoid it? Sure. The fraction only features powers and exponentials, so you can try to use the trick from the box "polynomials and ratios with powers": Determine the leading terms and factor them out.