Can someone tell me if these answers are right or not? these problems are getting on my nerves!

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1a. 3^1 / 3^2 = 3^1-2 = 3^-1 = 1/3^1 = 1/3.
2b. 4^2 / 4^4 = 4^2-4 = 4^-2 = 1/4^2.
3c. 6^3/6^5 = 6^3-5 = 6^-2 = 1/6^2.
4d. 3^-5 • 3^2 = 3^-10 = 1/3^10.

I believe for the last question its asking only to rewrite exponent as a positive exponent similar to the first question.

The correct answer will be d. -4