Answer:
![(-0.9)^(3)](https://img.qammunity.org/2021/formulas/mathematics/high-school/9z3ovl6r681wb98wfxmdgk4j1tl902ae3q.png)
Explanation:
We use exponents to symbolize how many times we're multiplying together. So 5 x 5 x 5 = 5^3. We have three 5s, so the exponent is 3.
This is the same logic: we have three -0.9s, so the exponent is 3. It needs to be outside the parenthesis so the negative is taken into consideration.