In an arithmetic sequence, the first term is 100 and the sixth term is 85. Find the common difference. Then, find the 50th term of the sequence.

Question

Do I use the formula an=a1+(n-1)d?
If so, what would my "n" by in the equation?

Answer 1

The nth term of an arithmetic progression is defined by N = a + (n-1)d where N = the nth term, a = the first term and d = the common difference.

Therefore,
85 = 100 + (6 - 1)d
-15 = 5d making d = -3

The 50th term then becomes
N(50) = 85 + (50 - 1)(-3) = ?

Answer 2

-402

Answer 3

ah what!!!!!!!!!!!!!!!!!!!