he ate 40 percent of the cookies
Answer:
The solution is 1.
Step-by-step explanation:
Logarithm:
Suppose we have a logarithmic equation in the following format:

It means that:

In this question:

Which means that:

Every number, elevated to 0, is 1. So

Which means that the solution is 
7 > z + 18 ≥ 6
Subtract 18 from all 3 parts:
7-18 > z +18 -18 ≥ 6-18
-11 > z ≥ -12
I hope you can read this, and I hope you understand how I did 7. I probably overworked it, and it was possibly a simpler way to get it.