Answer:
-1772
Step-by-step explanation:
The nth term of an arithmetic sequence is expressed as;
Tn = a+(n-1)d
a is the first term
n is the number of terms
d is the common difference
From the sequence
a = 28
d = 8-28 = -12-8 = -20
n =91(since we are looking for the 91st term)
Substrate
T91 = 28+(91-1)(-20)
T91 = 28+90(-20)
T91 = 28-1800
T91 = -1772
Hence the 91st term is -1772
