Question

in an arithmetic sequence the first term is 5 and the fourth term is 40. find the second term.

Please please please, don't give me answers but guide me into getting the answer (:

Answer 1

Find the arithmetic mean, that'll be the common difference. Then apply the formula.

Answer 2

what do you mean by arithmetic mean?

Answer 3

The formula for the nth term is:

\(\Large \color{Black}{\Rightarrow a_n = a_1 + (n - 1)d }\)

Answer 4

Arithmetic mean of 5, 5 + d, 5 + 2d, 40

Answer 5

OHHHH okay okay.