Question

Find the 20th term of the arithmetic sequence 7, 3, -1, -5, …
A. -73
B. -69
C. 24
D. 69

Answer 1

7, 3,-1,-5
decreased by 4 each time
arthymetic
an=a1+d(n-1)
a1=first term
d=common diffrence
n=which term

first term is 7
common difference is -4
an=7-4(n-1)
for 20th term
a20=7-4(20-1)
a20=7-4(19)
a20=7-76
a20=-69

answer is B