Question

Which choice is the simple formula for the nth term of the following arithmetic sequence?5, 1, -3, -7, -11, ... A.4n + 9 B.-4n + 1 C.5n + 4 D.4n + 1 E.-4n + 9

Answer 1

E. - 4n+9

Explanation:

Formula of nth term:

An: a +(n-1)d

Given:

a=5

d= a2-a1 = 1-5 = -4

Therefore, substituting the given values:-

An: 5 + (n-1) - 4

An: 5 - 4n + 4

An: 9 - 4n or

An: -4n + 9

Hence proved.

Hope this helps :)