I'll give you an example of a similar problem - that way you can see how it's done and then apply the same technique to this problem.

Suppse you have:

Its inverse is found by getting the x variable all by itself:

1. Subtract 10 from both side:

2. Divide both sides by -3:

3. Now take the natural log of both sides:

4. Since

, this means:

5. Divide by -2:

So now if you are given a value for y, you can determine the corresponding value of x. For example - suppose y = 4; then:

Hope this helps - can you apply this same technique to your problem?