The ninth and tenth terms of an arithmetic sequence are 1/4 and -1/3, respectively. What is the second term?
We have an arithmetic series
The common difference is -1/3 - 1/4 = - 7/12
So we have
a9 = a2 + (-7/12) ( 7)
1/4 = a2 - 49/12
3/12 = a2 - 49/12
(49 + 3) /12 = a2
52 /12 = a2 = 13/3
Find common ratio to be - 4/3
then x2 ( -4/3)7 = 1/4 shows x2 = - 2187/65536
