Question 158920
Read this --> http://en.wikipedia.org/wiki/Reciprocal_(mathematics)

The multiplicative inverse is just {{{1/x}}}. In this case, {{{x = -9}}}

so
{{{1/(-9)}}} = {{{-1/9}}}

Now to check, multiply {{{(-9) * (-1/9)}}}} Do you get 1? If so, you know you did it correctly