Answer:
Which one do we have to answer?
Step-by-step explanation:
First of all, I can't even see the whole question. Second of all, you didn't tell us what to answer. Please comment on this answer on which question you need help with.
As you probably know there is a difference between mean and median -- the mean acts as a measure of the average, and on the other hand median measures the middle number. The median in this is 15 and the mean is also 15.
The awnser is (-1+3/x-3/x2+1/x3 )
-3 because if you add -3 to 3 you get 0