Adding a negative number is the same as subtracting a positive number. So 2315.5 - 3166.75 = -851.25
X1= 0, X2= 9
I hope this helps!
Answer:

Step-by-step explanation:
Half the length of the palindrome can be any possible sequence of the 26 available letters. The other half is constrained to be the reverse of the same sequence. For odd length sequences, the middle letter can be any of the 26.
So, for k even, the number of palindromes is 26^(k/2). For k odd, the number is 26·26^((k-1)/2) = 26^)((k+1)/2).
Well, this is a stem and leaf problem.
The numbers are 20, 28, 29, 29, 31, 32, 36, 41, and 42.
In order to solve for the mean, we find the average and we add the numbers together and divide by 9(there are 9 numbers).
The mean is 32.
The median is the middle number, or 31.