What is the 20th term of the arithmetic sequence 2, –4, –10, … ?

1 Answer
Feb 8, 2016

Answer:

After the first term you obviously subtract #6# at every step.

Explanation:

At the 20th term you must have done this 19 times.
So the 20th term is #2-(19*6)=-112#

Watch it!
Most of the times the first term is called #t_0#.
This means that the 20th term is then #t_19#

But if they ask you for #t_20# (=21th) it's different:
#t_20=2-(20*6)=-118#