### Home > CCA2 > Chapter 2 > Lesson 2.2.1 > Problem2-100

2-100.

Write an equation for each of the following sequences.

1. $20,14,8,\dots$

Going from left to right, how much do the terms decrease?

Each term is $6$ less than the preceding one. This sequence is arithmetic.

$t(n)=−6(n−1)+20\ \ \text{or}\ \ t(n)=−6n+26$

1. $−6,−24,−96,\dots$

Is this geometric or arithmetic?

This is geometric because there is a common ratio (multiplier) between the increasing terms.

$t(n) = -1.5(4)^n \ \ \text{ or } \ \ -6(4)^{n-1}$