Question

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

Answer 1

first find the common difference

Answer 2

can you?

Answer 3

So we have a sequence here, an arithmetic one. 7 is where we start off and we notice that the terms decrease by 4.

Therefore, we see that for this arithmetic sequence, and for any arithmetic sequence, the terms are given in the order:\[\bf a, \ a+d, \ a+2d, \ a+3d...a+(n-1)d\]Where 'n' is the term number, 'd' is the common difference, and 'a' is the first term in the sequence.

Can you get the values of 'a', 'd', 'n' (Term number), and compute the value of the term?

Answer 4

@chicagoblkhaks