The answer for the question shown above is: B. Both powers should be in the dominator with positive exponent.
The explanation is shown below:
1. You have the following expression given in the problem above:
x⁻3y⁻9
2. The negative exponents indicates that x⁻3y⁻9 should be in the denominator with positive exponents. Therefore, you have:
x⁻3y⁻9=1/x^3y^9