Answer: -13
Step-by-step explanation:
Nth term will be:
Tn = a+(n-1)d
where,
Tn = 31
a = first term = 5
d = common difference= 2-5 = -3
Tn = a+(n-1)d
-31 = 5+(n-1)-3
-31 = 5-3n+3
Collect like terms
-31-5-3= -3n
-39 = -3n
n = -39/-3
n = 13
Middle term = (n+1)/2
= (13+1)/2
= 14/2
= 7
7th term will be
= a + (n-1)d
= a + (7-1)d
= a+6d
= 5 + 6(-3)
= 5-18
= -13
Therefore, the middle term is -13.