Solution:
Consider the number a. The multiplicative inverse of a is 1/a. Then, if a=-1.1, its multiplicative inverse would be:
[tex]a^{-1}=\frac{1}{-1.1}=\text{ -}\frac{1}{1.1}=\text{ -}\frac{10}{11}=\text{ -0.9}[/tex]so that, we can conclude that the correct answer is:
[tex]\text{-}\frac{1}{1.1}[/tex]