Answer: 81/16
Explanation:
When you have a negative exponent, it is equivelant to taking the reciprocal of the exponential and making the exponent positive:
Distribute the exponent to the base. We are able to do this because the base is composed of a single term. If it were composed of addition and subtraction, you cannot distribute the exponent:
Dividng by a fraction is equivalent to multiplying by the reciprocal: