## Precalculus (6th Edition) Blitzer

The difference between the consecutive terms is $-5$
Here, $a_2-a_1=3-8=-5;\\ a_3-a_2=-2-3=-5;\\a_4-a_3=-7-(-2)=-5;\\a_5-a_4=-12-(-7)=-5$ It has been seen that the difference between the consecutive terms is $-5$