The answer is negative 1. You divide the data set into 2 parts. Find the median of each and subtract the left side from the right
A(n)=a(1)+d(n-1), d=a(16)-a(15)=-5-(-53)=48
a(15)=a(1)+d*(15-1),
-53=a(1)+48*(15-1),
a(1)=-53-48*14= -725
a(n)=-725+48(n-1)
4m is the greatest common factor
