Question

Find a18 of the arithmetic sequence 2, -5, -12, -19

Answer 1

The 18th term of the sequence is -117.

Explanation:

The given sequence is 2,-5,-12,-19

From this AP,

First term, a = 2

Common difference, d = -5-2 = -7

It is required to find the 18th term of the sequence. The nth term of an AP is given by :

`a_n=a+(n-a)d\\\\a_(18)=a+17d\\\\a_(18)=2+17* (-7)\\\\a_(18)=-117`

So, the 18th term of the sequence is -117.