Question

Insira 6 meios aritméticos entre 13 e -8

Answer 1

an=a1+(n-1).r

an= -8
a1= 13
n= 8
r= ?

-8= 13+(8-1).r
-8= 13+7r
13+7r= -8
7r= -8-13
7r= -21
r= -21/7
r= -3

{13,10,7,4,1,-2,-5,-8}